Marquee still reigns as one of the top nightspots in Vegas. I have been to Marquee SEVERAL times and have never really had a bad experience. Yes, it's crowded, yes, it's expensive and yes you may feel a bit uncomfortable at times... But what else can you expect from a nightspot in a city full of tourists. Honestly, Marquee is very well staffed and they handle nearly all situations flawlessly. My recommendation to anyone is to get bottle service, preferably a cabana and just enjoy the hell out of your night. Great times can be had at Marquee, but this comes at an expected cost. Highly recommend either Marquee or XS for and EPIC night out in the city of sin.
Pros-
Location
People
Ambiance
Music
Atmosphere
Inside of the Cosmopolitan
Multi-levels
Outdoor area
Pool
Cabanas
Cons-
Crowded
A bit of the proverbial "shit show"
Pricey