Why our reviews are different
Search any engine for "best sister sites" and you'll find dozens of sites that look professional: tidy layouts, star ratings and confident recommendations. Spend five minutes comparing them, though, and the pattern shows up fast. The same casinos appear in the same order from one site to the next, the reviews are clearly written without playing at the casino for a single day, and the withdrawal experience, the very part that actually matters, is waved away with a vague "fast withdrawals" and no evidence at all.
The reason is simple: most comparison sites are affiliate businesses first and editorial publications second. Their revenue depends on steering the player to a casino, and that financial incentive shapes everything, which casinos get reviewed and how favourably they're presented. We're not claiming the affiliate model is inherently bad, since we earn from partner links too. The difference is how the conflict of interest is handled: most sites ignore it, while we built our entire methodology around neutralising it.
On top of that, we specialise in one thing others treat only superficially: sister sites, i.e. the networks run by the same operator. Alongside a standard casino review, we run a sister-site verification that general comparison sites don't offer. For the player this has direct practical significance, because it affects bonuses, self-exclusions and account management.
The "our own money on the line" principle
We don't rate a casino we haven't played at ourselves with real money. Every fully reviewed site goes through a genuine registration, deposit, play session and withdrawal attempt. Only this reveals the things marketing material won't tell you: how long verification actually takes, whether the first withdrawal is delayed, and whether the bonus terms deliver what the front page promises. Marketing copy can promise "lightning-fast withdrawals", but only a real payout shows whether there's a 72-hour processing time behind it.
This principle costs us money: every review requires a real deposit and the risk that comes with it. We consider that the foundation of our reviews' value. When something hasn't yet been tested or verified from a source, we mark it openly as pending and we don't guess figures. A blank field is more honest than a wrong number, which is why some rows in the register read "Pending" until the test is complete.
What a sister site means in a review
Sister sites are online casinos that share the same owner and operator. Brands run under the same company typically share the back-end platform, game library, payment methods and responsible-gambling tools, even if the look, name and promotions differ. This isn't just a curiosity, it concretely changes the player's risk profile and benefits, which is why it's part of every review we do.
In a review, the sister-site relationship affects three things. Bonuses are usually operator-specific, so another site from the same group won't normally grant a fresh welcome offer. Player-protection tools and KYC processes are often shared, which can speed up getting started on a second site. And most importantly, accounts can be technically linked to one another, which matters for both security and responsible gambling. We handle this as its own criterion further down.
The six-stage review process
Every fully reviewed casino goes through six stages. Each stage produces sub-scores, and together the stages form the final rating. The stages are always run in the same order, so that reviews are comparable with one another and no casino gets a shortcut.
Stage 1: Licence verification and legality
A review always starts with the licence, because without a valid licence no other feature is meaningful. We check the licence number directly from the regulator's public register, and we don't trust the logo in the site footer, which is easy to fake. For a New Zealand player, the most relevant is the Malta MGA licence, which can be verified in the MGA database by licence number. We record the licence issuer, number and validity, along with the operator's official company name and registration ID.
We also take New Zealand's particular situation into account. New Zealand's online gambling rules are summarised on our responsible-gambling page, and in practice the responsibility for checking a licence rests with the player. That's exactly why the verifiability of the licence is a threshold question for us: if the licence can't be found in a register, or if its details are contradictory, the site does not pass the review.
Stage 2: Sister-site verification
This is the unique part of our review. We work out which operator the casino belongs to and what its known sister sites are. Our sources are the operator's terms, company ID and licence details, which we cross-check against registers. We don't name a sister site on the basis of a similar look or name alone, we require company- and licence-level evidence. If a new name appears in the network as some operator's sister site, we check it against a register before we add it.
This stage also includes an operator reputation analysis, i.e. the so-called network effect. The quality of a single brand often tells you about the quality of the whole group, because the sites share the same back end, cashier and customer support. If an operator has a history of repeated withdrawal problems or unfair terms on one brand, that's a warning sign for all of its sister sites. Conversely, a stable, long-running operator raises confidence in the entire family.
Stage 3: Registration and verification
We test how smooth opening an account and identity verification (KYC) is. For a New Zealand player, the quickest route is often bank-based verification or Trustly, which links the deposit and verification to online-banking credentials without a separate sign-up. We assess how many steps registration takes, at which point identity has to be verified, and how clearly the site guides you through the process.
A key finding concerns the timing of verification. It's better for the player if KYC is done right at registration rather than only at the first withdrawal, where it often delays the payout. On Pay'n Play casinos we describe separately how registration-free play works and what it means for your data and withdrawals.
Stage 4: Deposits, withdrawals and payment speed
Money movement is the part that matters most in real use, and that's why it carries the second-highest weight in the review. We make a deposit and a withdrawal and measure how long the first payout takes after verification. We record the available payment methods, the minimum deposit and any withdrawal limits, processing times and monthly caps.
We pay particular attention to transparency: are the withdrawal terms stated clearly up front, or do the limits only turn up deep in the terms and conditions. Trustly- and bank-transfer-based sites typically score for speed, while long processing times, mandatory waiting periods or unclear terms lower the rating. We also consider the breadth of payment methods, since a wide range serves different players.
Stage 5: The bonus fine print
We don't just look at the percentage or the number of free spins, we read the terms in full. What matters is the wagering requirement and how it's calculated (whether it's based on the bonus, or the bonus and the deposit), the maximum bet during wagering, the wagering weighting of different games, the free-spin winnings cap, and the offer's validity period. We always give a concrete example of how much a bonus actually has to be wagered before a withdrawal.
We rate bonuses by the player's real value, not by the big headline figure. A wager-free free-spin offer is clearly worth more to the player than a deposit bonus with high wagering, and our review reflects that. We also consider ongoing perks, such as reload bonuses and cashback, and whether bonuses come with aggressive terms that in practice prevent withdrawing winnings.
Stage 6: Game library, mobile and customer support
We assess the breadth of the game library and its providers, the live casino, and how well the site and mobile use work. We check whether the games and cashier run smoothly on a phone, since a large share of play happens on mobile. For customer support we test availability and quality: does support answer in English, how quickly and how competently, and is there a live chat or just email.
Finally, we check the responsible-gambling tools: deposit, loss and time limits, play breaks, and closing the account temporarily or permanently. The existence, findability and functionality of these tools affect the rating, because they're part of player safety, not an optional extra.
Data security, encryption and fair play
The foundation of a safe casino is that the player's data and funds are protected. We check whether the site uses an encrypted connection (SSL/TLS) and whether it clearly explains how personal data is handled. An MGA licence requires the operator to, among other things, keep player funds separate from its own business, which means the player's money isn't at risk if the operator runs into payment difficulties.
On fair play, an MGA licence requires independent randomness testing of games, so game outcomes can't be manipulated by the operator. We also consider whether the licence gives the player a complaints route in the event of a dispute. These are concrete protections, not just badges in the site footer.
The account-linking risk on sister sites
This is a critical test tied to sister sites that general comparison sites don't run. Because the same operator's sites often share the back-end platform, accounts can be technically linked to one another. This has two consequences. From a responsible-gambling standpoint, a self-exclusion set on one site doesn't necessarily carry over automatically to another site in the group, so a player can accidentally get around a limit they set themselves. We always recommend setting limits separately on every site.
Secondly, if a player breaches the terms on one brand, the operator can close the accounts on the sister sites too. In every sister-site review we state how tightly the group's sites are connected and what that means for the player. This is exactly the information that marketing leaves out, but that genuinely matters.
How we compare sisters against each other
The core of a sister-site review isn't just scoring a single site, but comparing the brands of the same group against one another. When several casinos share an operator, a platform and often a bonus structure too, the player's question isn't "is this a good casino", but "which of the same family's sites is better for me". That's exactly the question we answer.
We line up the same operator's sites side by side and compare them on the factors that actually differ: the type and real value of the welcome offer, the breadth of payment methods, withdrawal speed, the emphasis of the game library and language support. Even though the back end is shared, the differences in these can be significant, and they're exactly what decides which site is worth choosing. One family site might emphasise wager-free free spins, another a classic deposit bonus and a third fast Trustly withdrawals, even though all three belong to the same company.
In every comparison we also highlight what the same group's sites share and what they don't. This helps the player understand when moving to another sister site brings genuine added value, for example a new welcome offer or better payment methods, and when it's essentially the same product in a different wrapper. That way the player saves time and doesn't open pointless accounts.
How we calculate the final score
The final rating on a 1 to 5 scale is made up of weighted components. The weighting reflects what actually matters to the player: safety and money movement weigh more than the number of games, because the wrong gambling site costs the player more than a limited game library.
- 30%Licence, security and verifiability of the sister-site relationship
- 25%Deposits, withdrawals and payment speed
- 20%Real bonus value and fairness of terms
- 15%Game library, providers and mobile experience
- 10%Customer support and responsible-gambling tools
A final rating isn't given until the site has been tested in full; before that, any editorial preliminary assessment is always marked as provisional. The same weighting applies to every casino, so that the ratings are comparable with one another. We never derive a score from a commercial relationship, only from tested findings and verified sources.
What leads to rejection
Some shortcomings are so serious that they can't be offset by other areas, and even a good game library won't save a site from them. We don't recommend a casino whose licence can't be found in a regulator's register, that sets unreasonable or hidden withdrawal terms, whose bonus terms are misleading, that has a repeated history of unpaid winnings, or that doesn't offer basic responsible-gambling tools.
If a problem like this surfaces during testing, it shows up clearly in the review regardless of our commercial relationship. We'd rather leave a casino unrecommended than steer a player to a site we wouldn't use ourselves.
Independence and how we earn
SisterSite is a commercial comparison site that earns from partner links. This doesn't affect the ratings, the scoring or the ordering, because the methodology is standardised and the scores are based on tested findings. Partner links are disclosed openly, and they don't add any cost for the player. We explain our funding model in more detail on the About us page, and all content is the responsibility of a named author.
Ongoing monitoring and regular updates
A review isn't a one-off. Operator structures change, licences change hands and brands get sold, so we go through the register regularly and mark the most recent review date on every analysis. A good example is an operator change: when a group's parent company or licence changes, it affects all of its sister sites, and we update the information with its sources and dates.
If you spot an error or out-of-date information, we correct it and mark the change visibly. The quality of the information matters more to us than speed, and an open corrections practice is part of trustworthiness. This way we aim to keep our register always up to date and every review able to withstand scrutiny.
The limits of the method, and honesty
No review method is perfect, and we don't present ours as one. A casino's quality can change after a review is published: bonus terms get updated, the owner changes, or the level of customer support wavers. For that reason every review is timestamped and tied to the moment the test was done. We don't claim the rating holds forever, only that it describes a verified situation on the review date.
We're also open about what we can't measure. We can't promise that every player gets exactly the same experience we did in our test, because withdrawal times and support queues vary. That's why we describe our findings as concrete, repeatable steps, not absolute promises. The aim is to give the player a realistic picture, not a polished advertisement.
Frequently asked questions about the review method
Does a commercial partnership affect the rating?
No. The rating is made up of a standardised, weighted score based on tested findings and verified sources. A partnership can affect which casino we get around to reviewing, but never what score it gets. If a casino is bad, that shows up in the review regardless of whether we earn from it.
How often are reviews updated?
We go through the register regularly and update a review whenever something material changes, for example the operator, licence or bonus structure. Every analysis shows the most recent review date, so you know how fresh the information is.
Why don't some casinos have a rating yet?
We don't give a final rating until the site has been tested in full with real money. Before that, some sites show an editorial preliminary assessment marked with the word "provisional" and based on verified sources; if there's no assessment, the field reads "Pending". This is a deliberate choice: openly marked incompleteness is more honest than a guess or a figure copied from elsewhere.
Do you test all sister sites yourselves?
We aim to test every site we recommend ourselves. Some sister sites in a network may only be source-verified but not yet tested, in which case we say so openly and mark the details as pending until we've done our own test.
What do I do if I find an error?
Get in touch and tell us the source. We correct errors and mark the change visibly. We treat corrections as part of trustworthiness and don't hide them.