I looked into these last year, and I decided I was going to give 'em a shot. However, I went to order one, and Cabelas was out! I took it as an omen, and I went with my other option, a Lone Wolf climber.
I love my climber, but I am still thinking about the Tree Saddle.
1. There's not hardly a negative review that I can find.
2. I think I'd feel pretty secure being buckled in all the time.
3. The weight factor for hunting rough, public land cannot be beat.
4. It would be cheap - $200 for the saddle. Then you could have as many stand locations as you want, only buying steps.
The only question is, how comfy can it be hanging out all day? There's really only one way to find out for sure, and that's try it yourself. I think (if it's made just right) it might not be a problem. I've got a couple of buddies who rock climb, and the've thought of doing this with their climbing harnesses for years. They swear they're comfortable enough.
I dont know if I'll try one this year or not, but it's still in the back of my mind.