If you are on the soutside then you have lots of possibilities. The most consistent is Garden Health Spa on State Highway 85. Sonia, the owner there, runs a tight ship. I have heard from some recent reports that quality slips a bit when she's not there.  Also, I'd recommend going during a slow time, like during the day or Saturday morning.  You're less likely to be parked in the sauna or left waiting then.