My husband and I did this Grand Romantic Evening on our honeymoon in October. I remember it being around $400 for both of us with the tips.
Although I thought the experience was "nice" I would not pay that kind of money to do it again.
First, they suggest that you arrive 30 minutes early to relax and enjoy the spa. What I forgot to ask is if they have a co-ed area where my husband and I could relax together- they don't.
The female locker room was adequate but on the small side with a hot tub for 4 people. There was coffee, tea, and juice to enjoy in the locker room.
At our appointed time we were lead to a candlelit room. It was actually two seperate massage rooms with the divider removed, so we weren't close enough to even realize we were in the same room. (Although, I am not aware of much in the middle of a massage).
The massage was fine. I've had better and worse in my hometown but this is the absolute most I have spent for a 50 minute massage.
It was hubby's first and he wasn't that comfortable with the experience so we probably could have spent the money better elsewhere.
The spa was clean enough and the grounds of the Grand Floridian are beautiful. They do recommend that you drink lots of water afterwards but you are to avoid caffeine and some teas do have that.
I thought the spa at the Wyndham looked more impressive (Downtown Disney) and I think that if you scheduled massages at the same time at any spa, it wouldn't be that different of an experience.
Good luck with your decision making!
Brenda