Mansion Poker

I'll add my input to the interface opinion. It is marvellous to play on a site that isn't cluttered and filled with useless avatars- AP, Full Tilt and Pokerroom take note!
The whole experience is so much nicer and aids concentration. The Poker Dome challenge is a unique online tournament with an all expenses VIP trip to Vegas and a live televised game going to the qualifiers.
Having qualified myself and gone to the Dome I can only say that the treatment that you receive surpasses your expectations. Mansion truly treat you like stars.
I like the fact that there aren't 1000s of players in a single tournament; I work for a living and can't be playing 11 hours straight through the night to cash.