Ehh...
That about describes it. The services are nice (Watsu is a specialty -- you should google it), but overall I wasn't impressed. The facilities are definitely not on par with other spas I've been to.
They have 4 whirlpool tubs all next to each other with varying temperatures. They also have a sauna and steam room. The steam room is one of the best I've been to (with a shower and all), but overall the facilities are just okay. Not great, not terrible.
If you're looking for more of a spa day, I would suggest going to either Aria or Caesar's Palace. Both of those spas are much, much better overall.