From the 3 mentioned one, the Partypoker is my favorite, even they have plenty problems, but the similar sized - not small, not big - rooms mostly disappeared in the last decade. They have low fees, leaderboards, not full with 2K+reggs on tourneys.
After GG, even dont like their software, just read in this week, they took over the weekly CG traffic from pokerstars for the first time, obviously much better than ps, and the size of the room is growing, soon will be number 1, still have much better rakebacks, promotions than ps.
ps. left long time ago. the only positive thing what i can mention about that, they still have the biggest player pool, especially tourneys. But i see, more and more players - even fun players - wake up, there are plenty better out there...