My 15-year old son and I spent one night in Vegas on our way to AZ and CA and decided to try this out. We went at night and the view from the top was a nice substitute for walking the strip (and avoiding the incessant cigarette smoke and nudie bar flyers). We also got to watch the Bellagio fountain show and it was much less crowded than in front of the fountains themselves.
Three caveats: 1. it's not cheap to go at night, but that's to be expected, 2. We had quite a wait, something like 45 mins, during which 3. we were on an elevated walkway overlooking the interior of the Paris Casino hall and pretty close to us was a dancer of the exotic sort. She wasn't nude but I guess I just wasn't expecting that to just be out there in the middle of the floor where anybody could see it, including the numerous kids besides mine that were there for the tower (many of grammar school age). C'est la vie, but be aware!