This pack has seen about 130 trail miles or so. I am 6' 1"and weigh in at 205-210 lbs. I have the 88 liter and got the size L which is the correct size for my vertebrae. I go on 1-2 extended trips of 4-5 days and 5-8 overnighters each season. Take note that I am not a UL or light weight hiker. I take fishing gear, food that needs more than boiling water to cook, a chair, or hammock (even with a tent) white gas stove, Extra everything, and a battery bank. I like my stuff and don't mind hauling it. I am stout and help carry other's gear if needed. I have owned this pack for 2 seasons. I take it to the Winds, and High Unitas as I live in Utah. This pack does a fine job hauling heavy (40-55 lb.) loads. It hugs my body well.
This thing is huge and that can be good or bad depending if one has the will power to NOT pack the Xenith to it's capacity. It carries the weight well. I love all the pockets this thing has. Love the belt pockets as well as the exterior pockets too. I wanted a pack that I could strap a sleeping pad or tent to the bottom. Many packs don't have straps on the bottom. Not sure why they don't. The Xenith does! This pack isn't the lightest or the airy-est. It's sweet spot is to carry heavy loads well. The sleeping bag compartment is large enough for me to cram my sleeping bag, Klymit sleeping pad, and a tent without the poles and stakes. If you are going to use the outside J-zipper pockets, pack them first, as it is difficult to stuff too much into them once the main compartment is bulging with gear. I love the mesh pockets for a fly rod, , chair or other tall or bulky gear. My only complaint is the bladder system. If you pack your Xenith and THEN try to fit a 2 liter camelbak into it, you REALLY have to work to get it to fit. I usually end up carrying a water bottles as it is hard to get the bladder back into the pouch when filled with gear, and bladder with water. I don't feel it was engineered correctly. The hip belt is stiff, which is a good thing. Very supportive.
If I were to improve this pack, it would be to have the brain convert to an actual day pack rather than a hip pack, Have 2 daisy chains on the rear, and have a bladder pocket that allows a full bladder to be inserted easier.
My favorite features are: it carries the heavy weight well, all the external pockets, the straps on the bottom of the pack, and the burly hip belt! Plus it's an Osprey, so I know they will back this pack up.
If you want a pack that will carry a LOT of weight well, this just might be the perfect pack for you!