The Las Vegas poker scene can be currently divided into four categories:

You have the "Big 4" poker rooms, which consists of the Bellagio, the Aria, the Venetian, and the Wynn. Great tournament structures, but bigger buy-in, mostly in the $125-$300 range. Of course they generally attract better players.

Then you have all the vanilla CET rooms, such as Bally's, Paris, Planet Hollywood, Harrahs, Caesars, Rio, all with terribly structured "donkament" tournaments, and fiercely-lacking customer service.

Then you have a bunch of locals places, such as the Orleans, South Point, etc. which have decent tournaments, but a very nitty clientele.

Then you have a the others, such as MGM Grand (A decently-structured 11 am tournament, and under-rated poker room IMO), The Mirage (a solid room, but is closed for a few months due to remodeling, as Ross said). Treasure Island came up with some neat tournament ideas, but the poker room manager was recently arrested for improprieties with players funds, etc. Not sure what is going on there now..