When I got these I immediately went climbing to try them out. Full range of motion is completely uninhibited and the fabric feels like it will stand up to quite a bit of abuse. I was really impressed by how free my movement felt. I got a medium and the sizing is good for me (6'2", 185lb, 32" waist). If your waist is larger than that, you might want to go with a large (although the material is stretchy enough to accommodate a few more inches).
The only reason I gave the pants 4 stars is the lack of pockets and fly. The one zip pocket is not enough to carry my wallet and cell phone, which is annoying. Also, the built in belt is kind of cheaply made and will easily loosen up when you don't want it to (the magnetic assisted clasp on the belt it cool, though).
Overall, they're a good pair of pants for the price if you get them discounted on S&C. I wouldn't hesitate to recommend them to someone else.