I hunted from a saddle almost all of last year and loved it. Comfort is something that has to be found in it. The pressure on your hips and quad will be determined by how well you adjust it to you. It is no different than a stands seat height or the cushion under your butt. I have found there are more important factors than just the saddle itself, like what does one stand on?
I tried the "ring of steps", the WE stepps(my fave up to this point), and currently have one of the new manufactured platforms on the way. I believe it'll be the best. I did manage to kill my biggest buck ever out of a DIY saddle this past year. I don't think he would have been un-killable had I been hunting in a tree stand, but it would have required a lot more movement had i been in one.
The key to minimizing movement is, just like everything else, trying to predict where the animal is coming from. One major difference is that when a deer does come from that direction, you can (semi) use the tree as concealment. There is no doubt that each style has it's own pro's and con's, but I like the weight advantage of the saddle much more than the weight of a tree stand. My sticks, saddle, and platform all weigh around #13. Most stands now days weight that.