FS has the edge over RC 22nd (Sports Club LA), but neither really shines for spa services. The health facility at FS has been updated recently, though it has not become (nor was it intended to be) a destination spa. The FS also seems to attract an older demographic which may be a plus, minus or neither depending on your personal preference.
Dont know anything about the Red Door other than it is most likely like the other Red Doors around the country.
Help your Aunt out with the tip and spring for the MO!