The Cosmopolitan is a very sleek hotel with modern architecture and nice, upgraded amenities. There's some neat artwork located around the hotel as well if you take the time to explore. Staff was relatively friendly, though the person checking us in may have downgraded our room a bit when we weren't willing to pay a cool $60 extra a night for a room facing the strip. We got a lovely view of Aria's parking lot for our stay, haha.
In regards to our room...perhaps my mind in the wrong place, but why is there a clear floor to ceiling window in the shower looking into the bedroom? Why is there wall to wall mirroring throughout the room? And are you sure that wallpaper is of dancers? The questions in my mind were a bit hilarious, if not immature. The beds were definitely comfortable though.
All in all, the Cosmopolitan is definite a chic place to stay in Vegas. It definitely seems to be catered to a younger crowd though. One plus for any person staying though is that it is located near the center of the strip. Walking from attraction to attraction on the strip is very convenient.