A very good monorail system, and it's even controlled by a computer! This system is useful, especially if you don't want to walk all the way up to the Stratosphere. If you want to ride multiple times in one day, then get the day pass. This is much cheaper than taking a very expensive taxi ride around the strip.
You will have to walk through a "maze" in order to get to the monorail stations, especially in MGM Grand, thus why I'm taking away one star.
But since each monorail train comes by every couple minutes, I certainly recommend this to anyone who doesn't want to take the expensive taxi or bus rides up and down the strip!