I was a zip line virgin and decided to grab a friend on the 4th of July and just do it! The wait was only an hour on a holiday night at midnight and the ride was a blast. I loved flying over everyone's heads on Fremont street and woohoo-ing!
The heights didn't scare me at all, but I did get a little scared near the end wondering how I was going to stop because I was ahead of everyone in my group and going kinda fast then ... Bam! Dead stop! So, definitely be aware of how it ends because you have to hold on to the strap you are dangling from to keep it away from your head.
Can't wait to try the zoomline next!