in this case, it depends on the player himself about his preferences when it comes to games or features. i believe, there's no concrete answer on this as the OP is vague with his question. if you will look at top casinos in the forum, they have their own features, rewards system, bonus programs and others. so what do you really want in a casino, an active support or a good VIP program? this is just an example. this is why most gamblers don't stay to only one. they will try another reputable casino to take advantage some of their features. now, it is up to you what particular feature you want to enjoy with.
We can only suggest a few lists of reputable casinos to OP so he can find himself the gambling features he needs but each casino has much different features, so it's hard to give a precise answer about OP's question because he doesn't ask clear questions, everyone gives explanation according to opinion each related to the superior features of the casino and maybe one of the answers above has represented the OP's answer, I hope he confirms in a new post in this thread to appreciate the efforts of others who have helped find the right source of answers.