I've tried the Obsidian and the Corrugate guide pant from First Lite. Both are great options, in fact the obsidian might be the most comfortable pair of pants in the world. Unfortunately I hunt rough and with work I am in dessert conditions one week, a snowy duck blind the week after and western Montana mountains the week after that. I burned through the crotch of three pairs of obsidians and one pair of corrugate pants in the last year. First Lite has been great and they always send me a new pair when I show them the damage done in the field. But constantly exchanging pants does get tedious.
The brush pants are lightweight like the other options from First Lite and do not restrict movement at all. I can climb 50 degree slopes or beat brush through sage and cactus hills without any movement inhibitors. I've put about 200 miles of walking on my pair of brush pants this year with little to no wear and tear to show. If I had to come up with a negative it would be that the back pockets don't zip so I have to put my wallet elsewhere when climbing around and due to the nature of the pants there are no thigh pockets. Normally this is where I put my headlamp but other than those two adjustments these are the best pants I've ever had. So if you beat the hell out of your hunting equipment and clothing like I do do yourself a favor and get these pants.