I hear a lot affiliate gripes about partypoker, but I have had success with there program, and no problems. I only have a handfull ofplayers at Partypoker, I have never promoted them strongly as I always felt the market was saturated. I have a good player value for what I have sent them, they pay for tournaments and blackjack (unlike Ultimatebet) from the begining (unlike pokeraffiliates). They are a well known and trusted brand with the players.
I also have had success with Pacific poker (888.com), but I think the complaints from them are there support of scrapper sites and black hat SEO methods.
By far my best converting program is Ultimatebet, but I would advise not to use them as they do not pay affiliates for Blackjack of tournaments, and this is a large chunk of your income. I promoted them for years before I found out they are stealing form me, and even admit it.
I would look into the prima sites offered by rewardsaffiliates, they are a solid program and they pay 35% from the start.
Good luck!