We had a fun time ziplining with guides Tristi and Shea. The guides were fun and outgoing and engaged teenagers, 20-somethings, 40-somthings and 50+-something, in our group of 8 people (this alone is kind of remarkable).
The guides encourage you, but don't push you beyond what you are comfortable doing. This was my first experience with official ziplining and i felt very safe. You are buckled you into a climbing harness and admonished to not touch metal stuff. As you climb and zip you are always clipped in to overhead ~13mm steel cables. 99.5% of the time you are clipped with two carabineers -- you need one unclipped to go between cable junctions. The unclipping and re-clipping is done by the guides very carefully and deliberately. There is always one clip attached to the cable and that one clip is sufficient to keep you from falling.
The zipline location is about 3 miles form the main road (Parks highway) on an ATV accessible. After getting off of the van from town, you ride for about 15 minutes one way on an ATV with your guides. The ATV ride is a bonus adventure.
i went in short-sleeve shirt and wished i had a sweater. Definitely, you want fairly rugged closed-toed shoes (running shoes or better). (follow their rules).
If you are somewhat active and adventurous, I would recommend this activity -- and our two guides (if you have a choice).