Glad to see I'm not the only one, UnderwaterBumblebee. I hated it, too, and would not choose to do a zipline again. In my case, I stupidly put my hand in front (in spite of directions NOT to do so)--if the glove hadn't been a little large, I would have sliced off a finger.
I also found the talk where they give you directions very brief and hurried. The guides--is that what you call them?--were very tense and also hurried. The whole thing just did not inspire a lot of confidence. And it really wasn't all that fun.
To tell you the truth, I had some idea that we would be leisurely zipping through the canopy, taking in the flora and fauna. Of course, the zip line is the complete opposite (duh!). I remember thinking that the people snorkeling were having a lot more fun and they didn't have to pay extra for it, either.