Many of them are on the up and up - a number of good review sites will list which ones and why, including this one.
I run a site myself, so I have to troll through a ton of casinos, decide which ones to play at (and risk real money, can't write an objective review using play money) and then wait and see how payment is made, how quick support is to respond, and other things like that.
Speaking of which the River Belle is totally unresponsive to any requests, including affiliate and tech support. Bryan, the Captain said he might change the company he outsources to, do you have any news on this? His affiliates program is on the verge of moving onto my "Not Recommended" list.
Good payouts only count if you're willing to spend a lot of time at them. By this I refer to chasing things such as a royal flush on video poker. What I would be more concerned with is how timely the payout process is.