Hi Scrappy Tink,
My husband & I have done the Spa Villas a couple of times, but both on the Magic. I'm a bit of a spa junkie, (I don't gamble, I go for a "sure thing" in the spas when I travel!

), and I will tell you the Spa Villas are to DIE for! Very pricey, but crazy luxurious. I think we did the one where you choose 2 treatments, but unless it's changed.....
Check in for your treatment at LEAST 15 min early. Gives you time to fill out forms, change, and for your therapists to talk to you about your special needs (you know, is it your shoulders that need the most work, etc?). I really recommend you get there more like a good 20 min before your treatment time.
You're escorted together to your sumptuous, private spa "villa", and taken out to the big private deck, where you will see a huge hot tub on one side, and a gorgeous double chaise lounger (with canopy for us, nice!). They did a ritual foot washing, again asking us what goals we had, like de-stressing, & then they picked out some lovely "potion" and emptied it into the hot tub. Told us we had approx 20 plus minutes to privately enjoy the hot tub together, then they would be back to start our treatments. Nice pitcher of ice water on the side of the hot tub too. LOVE-LY! Oh! BIG tip for you here. Do your very best to book your spa villa on a NON-PORT day, so you have maximum privacy. You don't really want to be looking onto another ship or buildings, or whatever.
After your hot tub time, the therapists return, & give you time to get the big, fluffy spa robes on to come inside to the treatment room, which in good weather, will remain open to the outside deck. Oh, & they do have glass doors they can pull closed both for the outside deck area, as well as for the interior room. All glass so your views are still wonderful! Then you are treated to 1 or 2 of the best spa treatments EVER! Afterward, put those fluffy robes back & you're escorted back out to the chaise, where you are served lovely hot tea & fruit kabobs while you relax, & let all that gloriousness just sink in...... ahhhhh.
Do I think it is worth it? You bet! Not something we could afford very often at all, but well worth a special splurge IMO. Again, don't forget to be sure & book for an "at sea" day for the most enjoyment! Bathing suits are optional during hot tub time!

Hope this helps you! I can't imagine the new ships spa villas being any less fabulous than those on the Magic. Have fun!