Ok.....

Obvious choices....

Stars/FT - Best choice, most players, best support, best banking. trustworthy. Cant be beaten.

UB/AP - soft games. Some worries over safety, id stay away.

Cake - dunno about cash games, ill wait for borgo to answer on that. Good improving site though.

Boss Network (para,canbet e.t.c) - not as many games, but apparently pretty soft.