I own four Osprey packs: This one is the largest (Xenon 85 M) and my least favorite ... by far. I think there must be a serious design flaw with this pack because it does not seem up to the standard I expect from Osprey. I had the pack professionally fitted to my body by EMS and we tested it with sand bag weights in the store. Then I hiked Mt. Marcy (8 hours in snow) and Mt Whitney (carrying around 50lbs for several days) with this pack. Especially when fully loaded the pack seems always unbalanced, despite the fact that I tightened the internal and external compression straps. The shoulder straps dug into my shoulders and chest constantly, so much you would not believe they were padded and no matter how much I loosened the chest strap, it is positioned in such a way that made it hard to breathe -- which is a serious issue when climbing at 10,000+ feet. The pack is also very heavy ... too heavy: it weighs in at over 6lbs with nothing in it. The water bottle holders are awkwardly positioned, so to get a water bottle you have to take the pack off. I also miss the fabric pockets on the hip belt that my Talon and Kestral packs have. Those are handy for quick access to snacks. The convertible top pocket/lumber pack is just dumb and unnecessary. And since it is designed to come off -- it never actually seems to stay "on" properly (the straps that connect it to the pack loosen during a hike). Osprey makes the best packs for women, that I have found so far. This pack however is not one of them.