I started with mine this year, and gradually gained confidence in it (API Grand Slam Extreme Magnum). I don't go nearly as high as these tree rats, but I get off the ground mostly so I can see further. I'm a big guy, and have worries regarding my weight that high in a tree (300 lbs).

When I hunt from low on the tree, I just have to be a little more conscious of being still, my cover (typically trees around me) and moving when I can get away with it. I would say that 15 feet is my MAX right now. As time goes by, I seem to be adding confidence as to the height I can go.

I would love to say 20-25 feet, but at that height, I'm so puckered that I'm afraid my arse is going to bite a hole in my seat. I just can't enjoy myself from that height.