I do best with Casino Rewards, and then the other larger Microgaming ones.
For Playtech, Blasters and Gaming Partners are a good choice.
There is no telling how any program may perform for you until you try it out. You’ll get as many opinions as there are webmasters.
It is good to pay attention to how they pay – carry overs and bundling are generally a negative, although I have made some decent money with some of these.