I am really uncertain which hotel would better suit my needs. Looking online at traveller's photos some of the bedrooms look a little run down for such a prestigous hotel so I thought the new Cosmopoltian would be better however some reports suggest that it can be rather noisy there, especially in the East Tower. Do you have any suggestions as I think I would be booking a standard room in either hotel.
The Bellagio just upgraded 500 of their guest rooms. I would call them and chat about the remodeled rooms and their rates. The Cosmo is new and their rooms should certainly be a good condition. However, The Cosmo does cater to a younger crowd and is probably noisier than the Bellagio throughout the hotel. I hope you have a great time while in Vegas.
I was just talking to both my son and friends at work about these earlier today.
The consensus is really the same--the Cosmopolitan is much the better spot to stay (rooms are fabulous), but the Bellagio is much preferable for food (the restaurants there are fantastic, while the food at the Cosmopolitan was rated as just "okay").
The comment about the Cosmopolitan being noisy mainly refers to their nightclub--where both my son and my friends think the music is turned up about 40 decibels too high--and where the people are totally insane--and the line to get in is ridiculous. Both groups recommended going over to the Rio or to Caesars for clubbing. They also both liked the pool at the Cosmopolitan and thought it even put the Mandalay Bay to shame (except for the Four Seasons pool at the Mandalay Bay). This really surprised me, since I considered the Mandalay (and Hard Rock) as having the best pools (previously) in Las Vegas. Their comment was that he wave pool and "lazy river" at the Mandalay are great for families, but not for young singles. Having a cabana was okay, but the Cosmopolitan was really set up better for the 21 to 31 age set.
P.S. They also said that the Aria is top-notch for staying at--and maybe even better than the Cosmopolitan--and it is also at the new "City Center". My son stayed there--but since he was there in March, the pool was closed, so he couldn't speak to how good that is compared to the other places.
[ Edit: add info on Aria ]