I just started playing again 3 months ago but here are reviews on the bigger 3 I play on. I’m not sure if they offer Mac versions or not though. Also I play at the micro SnG/MTT level.
Bovada
Pros: Best traffic for a US site. Generally has the weakest players. Best traffic at Micro SnG level. Best cashouts of the 3.
Cons: No Rakeback. Virtually no
freerolls. Micro MTT level is ok but not great. You can only play 4 SnGs or Cash games at a time (unlimited MTTs).
Pro or Con? : Anonymous Tables (Everyone is just a number). Tracking software on other players only works for that session so if you meet them again you have no stats on them.
Carbon (Merge network)
Pros: Decent Traffic. Best Micro MTTs of the 3. Ok micro SnG traffic. Can use tracking software.
Cons: No Rakeback. Slower Cashouts than Bovada. Only have freerolls during certain promotions.
Americas Cardroom (Winning Poker network)
Pros: Rakeback. Decent Micro MTTs if you include the On Demand SnG MTTs. Always a freeroll registering.
Cons: Worst micro SnG traffic of the 3. Slower Cashouts than Bovada. Least traffic of the 3.
All 3 have decent software with Bovada’s and Carbons being slightly better than ACRs.