Definitely THE nicest place to stay in downtown Vegas. It's a lot like the Cosmopolitan, except that it's in downtown and, therefore, cheaper.
They spent a ton of money and completely remodeled the interior so no more Lady Luck here. It's very hip and trendy. My room was nice -- not necessarily luxurious -- but aesthetically pretty, clean, and comfortable.
Like someone else noted, the only weird thing is the shower. It's like the shower only has half a door that's permanent. But other than not being able to aggressively rinse my hair, it was generally fine.
I'd definitely stay here again.