I would liken this experience to the end part of yoga where you kind of meditate or relax. The cave was very relaxing, quiet, and comfortable--so much so that I fell asleep while in there. In terms of the health benefits boasted by the website, I'm not so sure. I didn't feel any different afterwards, but maybe I just didn't know what I was looking for.
I gave three stars, not because the experience was poor, but because I'm not sure it's worth the money. Though there's currently a Groupon for a $10 session, so if you're looking to try it, now is the time.