My friend and I stayed at the Cosmo last week of November and had an amazing experience. The hotel is gorgeous, perfectly located in the middle of the Strip. Buffet breakfast at the Wicked Spoon was very good, although the price went up to $45/person on our last day there because it was the Thanksgiving weekend.
We had a City room on the 25th floor overlooking the Bellagio fountains which was wonderful. We were offered to upgrade our room, which is totally unnecessary since you don't spend much time in the room anyway.
Food and drinks were pricey but there are more affordable places in surrounding hotels.
All the bars in the hotel were great, but nothing can compare to the atmosphere at the Vespar, an awesome place to begin and end you night!
We loved every moment spent in the hotel and in the city. We are definitely coming back next year to enjoy the pool.