Positive and reliable ratings for me are already enough.
Rating sites don't seem very credible as a basis for trust, let's call it the most popular Trustpilot. Ad managers may employ sockpuppets to provide false ratings and reviews.
I even prefer to read user experience reviews on this forum as my main consideration for choosing a casino, where customer service is also a discussion.
Me too I would choose to believe those reviews from real experienced gamblers that already played on a site. For me those are more reliable than to those sites that are paid to by the casino itself to review them. I also see a lot of casino review sites which has a good review on those casinos that are known to be scamming people.
Discussing that, I've seen one thread recently on Services board that offers some crypto for real users to publish a review to his site.
This is the thread: https://bitcointalksearch.org/topic/write-a-short-crypto-casino-feedback-paying-5-directly-to-your-btc-wallet-5382433