Based on the lower zip line experience, I'd rate this two stars. I wanted to do the upper experience where you're semi-prone and have a much longer ride, but it was either booked for this timeframe or closed for the evening.
It was o.k., and $20 isn't that much, but we had an 11:00 PM reservation and didn't get our turn until 11:45. The ride was very short and just not worth the effort. Staff was professional.