I used to be pretty wary of hang-ons and climbers. I've found that with practice, especially in the daylight, you can become fairly comfortable using them. My suggestion re: climbers is that you practice with it under non-hunting conditions (so that you're not worried about noise, etc) and start off low. Once you're comfortable with the technique involved with ascending and descending, you can concentrate on using it quietly, and working on getting it up a little higher.

I think if you try using it once or twice for practice, and then try ascending a tall tree in the dark, you're going to just end up needlessly scaring yourself s**tless. Just borrow someone's, and go slow and easy and you'll determine if you like using one.