I bought it for hiking/mountaineering use. The ventilation system on the back is EXCELLENT, you hardly sweat at all. How well it sits on your back when you adjust all four straps correctly is incredible, you don't feel like you're carrying anything, it doesn't bother you in any movement. I wore it for 8 hours straight and didn't notice anything. Quality construction and materials. Large storage spaces.

Update: After almost 2 years of use with over 1000 km of hikes in scrub, forests, and peaks, the backpack is almost like the first day. I wouldn't change it for anything.