Saratoga is the one who won 5th place from Conde Nast for Resort Spas- it was really wonderful when I was there earlier this month. The treatments offered are a little bit different at each one...for example, the body scrub at SSR is a Maple Sugar Scrub, at GF it's Citrus. Have you looked at the website with all the services yet?
Both were wonderful as far as services go but the people at Saratoga were a bit friendlier than those at the Grand Floridian if that makes a difference to you.
I had a really poor experience at GF last spring and went to Saratoga last December. Saratoga is by far a more enjoyable experience and feels like a spa. Just my opinion