The site lies in a dark green pine forest, with air as healthy as you normally can only wish. There's a huge parking lot, but at the end of December, I was one of only a few guests. I had the amphitheater, which sits 14.000 people, to myself. It's like a football stadium, without the fences and the advertising. Unbelievably well preserved also.
Besides the theatre, you can visit a museum with local findings (mainly statues) and the excavations. Not much is in place of the hospitals, hostels, bathrooms, and what more was needed to serve the stream of visitors looking to improve their health.
The location of the site is its major drawing card. It's like a retreat, like the secluded places where they construct monasteries in Japan or South Korea.