Prism and Cool cat casinos can be a problem to get cash outs. I cannot guarantee payment from any casino, I run a casino bonus comparison web site, I don't take bets of any kind and the reason I don't rouge these 2 casino is to try to help user out when I can by stepping in asking a casino on a player’s behalf about pending cash outs, as these 2 casinos in particular gain allot of attention due to the no deposit bonuses they continually give away.
But if you want to play RTG then you have great operations like
Club USA,
Slots Plus and
Sun Palace Casinos that I have never heard people have any problems with.