Since the new Virgin Poker launched last year I've moved over to play mainly on the site (used to be on Tribeca via VC). The main reason for this is simply that i can earn more money on Virgin as the opposition's not as good.
At the $10 stt and mtt level the opposition is fairly loose and definitely beatable - more so than on other site's i play on. There's also seven card stud and five card draw which are good fun.
Virgin has the best loyalty scheme of any site I've played on. It's totally transparent and you can convert loyalty points to cash (1point=1pence) which is handy if like me, you don't earn that many as you play low stakes, and just want to top up your bankroll. For the higher rollers they offer an exchange scheme with Virgin Atlantic flights, and reckon a pro can earn a return trip to Vegas every two months - Not that i'm anywhere near that level, but it sounds good.
Site stability is good - i've had one crash in 6 months and got my money straight back from customer services.
The software is pretty straight forward, quite a clean design and more like VC than say, Full Tilt or Party which i personally find really cluttered.
Liquidity wise there's usually 3-6000 people on the network (Boss). STTs fill up very quickly and a standard $10 mtt tends to get about 150-200 runners. They have all the WSOP, WPT and EPT qualifiers and some big tournaments up to $250k i think.
The only drawback with the site is a lack of player notes, but there's a player search function that helps you pick your favourite opposition. Also i don't think Poker Tracker supports Boss, but i'm not sure
All in all i like this site and it's my regular poker site. I find it possible to make a profit here, the customer service is good and the loyalty is the only scheme that actually makes sense. They also have a blog on the site which is quite entertaining and some good free roll tournies for loyalty points (which can be turned into flights or cash).