Did you check out Post 4 (Amenities) on the FAQ thread? I have a few short reviews of the spa services posted there.
General consensus is that the services are excellent, but pricey.
I believe there is also a spa at the Swalfin (not sure which one) but I don't know any more about it.
I add reviews as I see them, so I would love it if others posted about there experiences here.