I've been to lots of conventions/conferences in Vegas, and have stayed at:
The Venetian
Caesar's Palace
Harrah's (yuck!)
Mandalay Bay
Rio
When I went for a long weekend and I had to pay, I went back to The Venetian. Best location, best rooms, best everything!!!
I would not go back to Mandalay Bay -- too remote (end of the strip), the shopping is not great, the rooms are so-so by comparison. The soap, shampoo and conditioner were the best, though.
