I've never stayed at Circus Circus, but confident that it is a total pit. I stayed at Excalibur in about 1995 and thought it was pretty bad then. As it's older, and my standards have increased, I'm sure it's worse now.
As I mentioned, Harrahs has the shuttle to the Rio. Probably your winner of those 3. Worth noting, 99.9% sure the shuttle won't let you transport your luggage. People take small shopping bags and whatnot, so maybe you could stash almost everything w/ Rio bellhops (not sure if they would do this) and just use a very small bag for the weekend.
As for poker room rates:
http://www.pokeratlas.com/poker-room...s-vegas-nevada