My favorite Spa. Hands down. Period.
This spa is SO clean. The people are SO professional. The spa is so large that I truly would have been lost if I wasn't being guided by a staff member.
We spent a full day at the Bellagio spa. The spa is only available to people staying at the hotel, so it wasn't a problem booking our treatments. I've been to a few spas, but the Bellagio spa is by far the best and largest I've been to. I would definitely go back just for the Vichy shower and relaxation rooms. I had a Vichy shower, sea weed body wrap, facial, manicure, and pedicure. All of the services were excellent.
If you can only afford ($ or time) to do one thing at the spa... it's got to be the Vichy shower. You go into a room with a table with multiple shower heads above it. The table is covered with towels and is very comfortable. You lay on it and choose a scrub. The spa technician then uses the exfoliant and scrubs your whole body. It's a massage with a scrub with shower heads all hitting you at once. It's perfect. I've tried the Vichy shower in many other places and this is the best one.
Yes, it's expensive, but it's the Bellagio in Las Vegas. It's not going to be a $20 massage. I think it is expensive but worth the price.