The mechanical contraptions you're talking about are climbers descenders. Mountain climbers use them. Very expensive as is the rope. You still need a rope attached up high to use going up or down. I bought one of the Summit 30 foot ropes with the Prusic knot to use as a means of escape from the tree should my climber fall. Added a couple of their descender ropes to allow me to inch down the tree. I think I'll use the 30 foot rope as an attachment to my HSS vest as I climb. That way at any point if something fails I'm already attached for a descent. When I get to my height I'll pull the rope up and stuff it in it's carry bag attached to my stand. If the stand gives way the rope will or can be paid out down to the ground. The descender ropes will allow me to put slack in the big rope and move it down as I climb down. It's probably an over kill because I rarely go above 22 feet. Usually stop somewhere between 18-22, At those heights I'd be able to use my normal prusic rope to get down to a height I could drop from safely without breaking anything, but you never know. All the way down is better than free falling the last few feet.