I don't read any reviews since I don't really like switching around to different casinos. I like to stay at the same place and work on refining my strategy at that specific place.
That's not a problem if you don't like to switch to one casino to another casino. If you like to stay there, that's nice.
But if the time comes and you're wanting for a switch, don't forget to check reviews.
But where to check the reviews is the main question, I can suggest a few like trustpilot and ask gamblers both of them are good but the problem is that any recent problems and issues with the casino might not be mentioned in the trust score there so I always prefer to check the ANN of the casino here in bitcointalk and go through it quickly to find if there is any problem with the casino.
Also when you switch casino you can switch to the same owner for example I used to gamble at primedice but when I felt the need for sports betting as well, I just switched to stake.com and they have the same trustworthiness of primedice because they both belong to the same owner.