I've yet to find a better poker room than the Wynn/Encore in my 25+ years of playing poker. The staff is excellent!! They are professional, prompt, and have the attitude that "the game is the players" (within reason of course). Food is expensive but you get what you pay for. As an offset, the comps as pretty good, and when you consider there is a poker rate for the hotel, it's not all that bad.
As far as the games themselves, bring your A-game. Lots of pros, in the higher stakes especially. But overall friendly and welcoming in my experience.