Revenue Sharing — gives you a certain percentage of the net gaming revenue generated by the casino from your referred players, usually on a monthly basis throughout your referrals' lifetime in the casino.
CPA Deal — gives you a fixed one-time incentive for every player you refer to the casino.
Hybrid Deal — a combination of the revenue sharing and CPA deal. The revenue share is not that high and so is the CPA — for balance.
All of them are good but I think generated revenues sharing in an agree ratio is better. Many affiliate program also prefer this format than others one. I still believed that more ways to earn with casino or gambling affiliated program are going to come up in future.