The zip line itself is great. I did it twice last weekend. I was perfectly happy after the first experience, but I was less happy with my second ride.
The problem is that they don't tell you that you may have to wait about an hour after your "boarding time" before you actually get to zip line. Apparently that disclaimer is buried somewhere on the website, but you aren't going to see it unless you're actively looking for it. It's rather absurd that when they limit the number of people who can buy tickets for a 20-min period that they can't get people through the ride efficiently. When we complained about the wait the staff acted shocked that we dare complain about it.
Overall, i think it's worth it if you can do it during a weekday when it's not crowded, but I wouldn't bother with it on the weekend when it's crowded.