The wife "dragged" me to the spa with her when we went to Vegas recently. I expected the men's side to be quiet and dead on a Sunday afternoon, but they were really packed.
It sounds like the men's side is just as good as the women's: there's a roman jacuzzi/bath with 3 different pools of varying temperatures and heated stone loungers that are a great place to nap.
There were several different sauna in here: a dry, a steam, and an "inhalation" room which really opened up my sinuses. There's also an arctic room which didn't feel very arctic and apparently normally has snow coming out of it. The men's didn't, which was my only down side.
The massage itself was kinda "meh". We got a couple's massage and most of it was good, but I always say that in Vegas you're paying more for the experience than a true quality massage that can work the kinks out.
I can definitely see being dragged here again!