We really enjoyed our time. It was our first time ziplining and our guides made us feel comfortable. We booked via their website and opted for off peak as they were 20% cheaper.
You need to walk back up the steep hill so you need to have a reasonable level of fitness.
Tips. If you do 6 ziplines (Kea - I think) tour, might be best to do in arvo (or at the end of your day) as you will finish on the foot of the mountain. Will take approx 45 to get back up by foot. Your gondola ticket only valid for 1 return trip!
Also, parking is SUPER frustrating as off street parking is only for 240 mts while Kea tour takes 2.5-3 hours. Barely enough time to do everything before you get a parking ticket! More