Nice. Oh so very nice. Not as nice as the Aria or Vdara, but damn close. The only thing though about the Cosmopolitan is that it felt very cluttered and congested. It was hard to navigate through the casino and multiple floors of well, everything. We couldn't even find the sushi bar that we wanted to eat at and we couldn't locate any employees to ask for directions.
Still a nice hotel though. I can't imagine what it would be like to stay here. One of the few hotels in Vegas that actually have a balcony and a minibar. Pretty sweet.