I love Mandalay Bay because it was one of the first hotels my family and I stay at, and continue to stay at. There is a home-y feel to the hotel plus it has a man-made beach. Each room is luxurious compared to other hotels. The prices are not too bad and you can definitely find cheaper rooms ($40 and up) during the weekday.
Con: It is at the end of the strip which makes it a little hard to walk to places. It takes about 15 minutes to get the strip on foot but you are able to take the tram to Luxor and Excalibur which is a huge help. This hotel is more for a romantic getaway or family vacation.
One of the best hotels. Get a M LIFE card!