Have you tried looking into the Burke Williams Spa?
It's at the Block in Orange. They have a fantastic spa. It has a steam, sauna, gigantic hot tub, relaxation area, multiple showers & vanities to get ready. All for a price lower than mandara. It's about 10 min away driving if that. The taxi may make it so the price is comparable to mandara but the experience beats it by far.
Also, the block has shopping, dining, & movies if you want to make a day of it.
Now granted, I have never had a massage at mandara but have had a tour of their place. maybe they have

masseurs? and if you're looking for just a quick 1-2 hour break from disney then maybe mandara is the place for you. but i've never been let down at any burke williams.
oh yeah, if you're going before christmas eve. i can send you a coupon for 25% a massage for you & your dd or 20% one person at bw.