Has anybody ever tried one? I think it might be hard to shoot on your off side...

i've never tried one, but i know that the guy who wrote the Precision Bowhunting book used them religiously. If i was you i would look that book up and see what you can learn from it.

the seem like the would be hard to shoot out of but on the video it looked easy

Have one- it has it's place for sure- takes a while to get used to- Fits good in the arsenal. Not for every setup- but has it's place in the right setting. Good luck.

I would think youre legs would get tired from pushing off of the tree.

I have one and love it. It's not for everybody. If you like being very mobile and lightweight it's great. Shooting to your off side is actually easier for me because you have more options. You can silently "walk" around to the other side of the tree and get on your good side. Or you can pivot in the saddle shoot to your other side. It sounds hard but I shot a buck that way last year. The thing is dead silent and extremely light. It's fairly comfortable as long as you adjust positions every half hour or 45 minutes. I still use fixed position stands but if you want to get deep into the woods away from other hunters it can't be beat. Also, you don't have to worry about people hunting your trees when you're not there. I think a tree saddle and strap on steps or a lone wolf stick is the ultimate mobile setup.