There is no answer to this.
Different programs perform differently on different sites.
I do extremely well with the free spin promotions.
All of the Micros are doing way better for me than other softwares, but playtech is slowly improving for me now.
I try to avoid bundling.
Negative carryovers are the pits – I have spent months and months in the minus with bigger winners. Forget that, it’s as likely to happen to you as a whale, sooner or later it gets you. Then I pull the program to at least rescue income from new players, but meanwhile I have done all that work sending quality players who are now loyal to those casinos and I see nothing for it.
I like a place that lets me build a player base. Retention is ultimately, in the long run, more important than conversion.
There is no short cut to evaluating programs for your site. Its a trial and error situation, my favorites have already been discounted in this thread and if I were to go by that I would have half the income.
There are some criterias though we all should watch out for: Bundling, negative carryovers, clauses that require you to send a minimum number of players in order to get paid for previous players sent (I really hate that one, get sick or lose ranking or something and no more pay for players already delivered. Pure theft in my eyes.) and miscellaneous lousy conditions.