Johno has had a few climbs using the Unicender and says it will take some getting used to. There are two modes: CONTROL and ADVANCED. Control uses the rope tail to manage speed in descent and works as the name suggests. It's the advanced mode where the challenges begin. Descent speed is managed by squeezing the Unicender 'handles' between the tips of your fingers and the palm of your hand. Here's an except from the Unicender User Manual:"It is human nature to grab (squeeze) harder when surprised or panicked. With a squeeze to go mode like ADVANCED MODE this could be disastrous, if you squeeze the handles together in a panic you will come down too fast (also known as falling). For the UNICENDER climbing tool, to stop your descent you must let go of the handles (very Zen). It takes training to overcome the grab instinct. But in the mean time we have the squeeze to stop mode of descent: CONTROL MODE. This mode uses your grab instinct to stop your descent. Safer by design." This says it all.
In the process of learning more about the Unicender Johno came across this video on YouTube - certainly gives you comfort!