Being an big Mandalay Bay fan in general I would pick either Mandalay Bay or Luxor. I stayed at Luxor when it first opened and was less than impressed with the rooms. We walked about 1/4 mile after getting off the elevator just to get to our room. Way to far for me. I have never heard anything bad about Mandalay Bay - and for the $250 average room rate I would not expect to. If you are a low roller you may want to consider Excaliber. Much cheaper than any other choice you mentioned and connected to the same monorail system between the 3 hotels.