OK so the Oasis spa now called Nurture spa at the Luxor, i guess.
in any case, the services are pretty good (facial and massage) and amenities are good (hot tub and a huge sauna that comes equipped with ice cold face towels and cold bottled water).
The reason why it only gets 3 stars is the ambiance of the spa. First of all, it takes 10 minutes to even get to it and you feel a little like a mouse in a maze. Second of all, it's just a little too dungeon-ey. You feel like you're in the basement or something because there are no windows and the bright, white hallways look like hallways in a hospital.
The staff are friendly enough but they do hire some really young girls who haven't yet learned the fine art of customer service appropriate for a spa. They are really just there to fold towels and refill the cotton swab container.
if you're looking for no frills, Nurture is good place. The prices are reasonable and the treatments in and of themselves are good. But if you're looking for the full experience, this might not be the place for you.