when we were there in sept the zip line was still down.
this is just my opinion.
we saw where the zip line was during our taxi tour. it looked a bit ricketty....
I am afraid of heights so i would not do it anyway but...you are not in kansas anymore.
they do not have national standards, safety checks or inspections, and its all about grabbing the tourist dollars. I know people have done it and had a great time, but I think I would do a zip line with a guide or a tour company that people have done. Like Reggies, I have never done a tour with him but people seem to have a great time with his tours and feel very safe.
do your research before you choose.