This is the best hotel off the Las Vegas Strip by far. You don't even really need a car to stay here. Since the place is a Harrah's property you can take a shuttle out back to any of the other property hotels which is a huge plus. If it's one of the 5 days the weather is nice in Las Vegas you can even easily walk to the Strip in 8-10 minutes and it has a sidewalk the whole distance.
The rooms are all suites and amazing no matter where you wind up in the hotel. While the price falls similar to Strip hotels the Rio wins for me every time with quality and size.
The added bonus is that the Rio always has great and entertaining stuff going on. Quality poker room, fantastic food selections (including what I feel is the best buffet in Vegas), and great pools just make this place a trifecta. Believe me when I say once you give this place a chance you won't care it's on the wrong side of I-15.