As mentioned, I stayed at the Rio on Labor Day and loved it. The room was uber reasonable and large. There is a window in the shower so you can see out to the bed. I liked jumping up to the window to scare my husband when he was showering, but I don't think it was made for such antics.
The Rio had much to do for the non-gambler (me) , there is a 'show in the sky" that has floats coming out of the ceiling - and I never was bored with how many times I saw the show. It is free.
Also, the bartenders do the 'Cocktail' flair thing- throwing bottles etc. When my husband was at a table, I parked myself at the Octagon Bar and watched the bartenders.
There are two nightclubs at the Rio, Bikinis and The Voodoo Lounge. The latter is at the top of the hotel and has a view of the strip. Bikinis has woman in bikinis dancing in water. Both were a lot of fun.
We visited the Mandalay, and liked that hotel as well.
One thing is for sure, you will have a wonderful time!