I spend most my time on Party, but like you..whenever I feel like a good stg I head over to stars. Much better tournaments, mainly because of the amount of chips you get to start with.
Not a fan of Prima at all, its really because of the software. It just seems so outdated and old, turns me right off. Cashouts seem to take longer too compared to some of the bigger guys.
I play my limit games at Party, just started picking up my frequency of playing. I have started playing some NL and Rounders (progressive SNGs) at Battlefield Poker (Prima). I really enjoy the Rounders format at Prima and am building towards the 3000$ 1st prize I hope.
Party Poker is my least favorite! I can never win there... never ever never ever never...
It is funny though coz every 6 months approx. they send me some kind of a bonus to play with at their site for free... and I always seem to lose it in about 30 minutes.
I really struggled with Party/Empire before they split. I then realized a lot of it comes down to table and seat selection. I always try avoid sitting to the right of an aggressive player or the big stack at the table. This usually keeps me from getting raised after limping UTG or UTG+1.