I selected the Rio based on one thing--a special $50/night rate for the mountain view rooms (I'm cheap, what can I say). At check-in I did the $20 "trick" and ended up with a suite on the 33rd floor overlooking the strip. The room wasn't anything fancy, but it was huge and the view was great. The bed was also more comfortable than it looked.
Overall I was not that impressed with the Rio. The food choices seemed pretty crappy. The seafood buffet is suppose to be good, but the line was about an hour long so we skipped it. Also, the casino is pretty far off the strip. They have a shuttle to a couple of other casinos, but it stops at 4 or 1 am, depending on the night, so we ended up having to take taxis back to the hotel. With how much we spent taking cabs around we might as well have spent a bit more on a strip hotel.