MY favorite room in Vegas are downtown. Binion's and the Golden Nugget both have great staffs. The dealers at Binion's are usually a lot more personably, and able to have more fun as the game goes on. This allows for some looser play, and for time to pass a little faster if you're looking to kill time. The Brush, no matter what shift, is always quick to respond to any issues that may arise. The Nugget has excellent dealers and they act a little more professional. This doesn't increase the "fun" aspect, but the game has a more serious feel to it and the play reflects that. The Brush there is very organized and runs a smooth operation.
I've enjoyed other cards room in Vegas, but those are, IMHO, the far and away leaders when it comes to service.