I stayed at the Hard Rock on a Wednesday after two days at The Hotel at Mandalay Bay. The experience was positive. It is a younger crowd, and a bit loud so if you are looking for quiet, this is not the place.
The rooms were large and clean with nice beds. I stayed in the Casino Tower. I am a bit older than the 20 somethings that were mostly there, but I enjoyed the energy.
I played in the casino at the table games and found the dealers and pit to be more kicked back and enjoying themselves. This made the whole experience fun. It was mid week so not very crowded.More