The Rio is a pretty decent hotel. The rooms are spacious and the whole hotel is very clean. It is a mid range priced hotel, but using Total Rewards you can get a number of nights comped if you are staying for a while, which makes it quite a cheap option.
The club on the roof has amazing views of Vegas, so I definitely recommend taking a trip up there to take a gander.
I do have to say though that the location is a bit of a pain in the derriere. It is a good 15-20 minute walk to the strip and the main road is a little sketchy, so I would not advise walking it on your own. There is a free shuttle bus that takes you to Bally's and Paris Hotel's every 30 minutes, so that helps, but it can be a little on the slow side.