Mandalay Bay is a very comfortable hotel. The accommodations here are very generous for the price. The rooms, casino, and pool are very well kept and the spa is one of the best on the strip, second to possibly Aria hotels spa. If you plan on staying at Mandalay Bay, try and make sure to still venture down the strip. There is a lot of action around Mandalay... Luxor, Excalibur, etc which are easily visited by a free tram or people movers, however so many people just get stuck at the tail end of the strip do to the location.
The Pool: Hands down the best pool I've visited. If you plan to go on the weekend or peak season be prepare for a fraternity type of environment with random drunk altercations that usually dont get any further than yelling.
Ambiance: the hotel checkin area is a Kodak destination in itself... Beautiful aquariums and decor are all throughout the hotel and casino.
Be sure to check out the shark reef while you are there. The reed is really only about an hour or so experience so be forewarned not to be too disappointed when it's not like a huge aquarium exhibit... It's Vegas :)
Great for families!!! Especially on week day visits or off season get aways!

Stayed 5 days in November, with the pool area being closed. Still had to pay an additional "resort fee", even though no resort facilities was in operation.

The marginally more expensive THEhotel in the same complex would have been a better choice between the two of them.

I stay here almost every time I go to Vegas. For business or pleasure they have everything we need. When I bring the fam on business trips, they have the best pool in Vegas. The rooms are always clean and updated with the latest TV's and electronics. The beds and very comfortable. But most of all, they go out of their way to treat everyone well. I recommend Red Square and Ri Ra, both outstanding. The Asian place not so much.

Nice rooms and very clean hotel. Lots of restaurants but limited mid-price food offerings - walked over to the Luxor to get basic fast food.Really nice pool area. Nice Casino and not too smoky.
Long walk from the hotel area to the conference area. Aquarium inside the hotel takes about 15 minutes to walk through - not really worth the money.
Check in at 11pm took 45 minutes. Check out was fast. Would probably not stay here again because it is too far down the strip.