Buddy had one and I tried it because he was going to sell it as he didn't like it. IMHO there is TOO much movement. Comfortable for sure but I tried it 5 times and each time I was busted for movement/sound. The only way it worked for me is when I had two trees close together so that I could brace my body against the other tree. I still prefer a ladder or hang on.
I think one of the major disadvantages of them is they can be very time consuming, very awkward to shoot from and yes, tuff on your legs, tried one once and never again. They would be decent for elk hunting or something quick....but, for whitetail I think a climber may be better. My junk didn't like it either jackalope