I personally prefer to play multiple sites at once. Stars is obviously the go to site for volume, but this is only because it is full of solid grinders who are also multitabling.
Stars is definitely beatable, however it is much more profitable to play on multiple sites with less volume against weaker opponents. At the moment I am playing low stakes sit n go's running 888, Winamax and ipoker.
For each of the three sites the tables are stacked, and I aim to play around 12-15 tables. The only down side is it is sometimes difficult to calculate how man tables you have open at any one time. It may take a little practice but I personally think this is the best way to maximise your profits playing low stakes.
Medium stakes run rarely on these sites however, so if you intend to move up rather than making some nice pocket money then Stars would be my room of choice.
Any smaller rooms are fine to play, its personal preferance for software, rakeback ect.
Check out pokerscout.com to view rooms with the most traffic!
Good luck ♠_thumbsup: