PokerStars hands down for non-US players. Merge, despite all of their blunders, is still a very good network. WPN is working their way up. Their player base isn't as large as Merge's and their software isn't anywhere near as good. But the people who run it seem to be very dedicated to making it the best site. As far as Bovada goes, I'll never get used to their anonymous tables and I'm always suspicious of other players when I am at the mercy of the site to protect me from collusion.