I was in the market for a large expedition pack for glacier mountaineering. I have a 17-17.5" torso, so I chose to go with the Small pack. However, my 32" waist and larger chest/shoulders require a medium belt/shoulder pads. I contacted Gregory and sent them my small straps, and (after a few hiccups), got some medium shoulder straps and hip belts.Unlike some other packs I tried - that claim to be adjustable for wider ranges of torsos - this one actually felt comfortable carrying loads when sized for me. For example, I tried a Lowa Alpine Cerro Torre and found it really fatigued my shoulders and sagged/swayed under loads heavier than ~60pounds.Before I bought this pack I read reviews and strongly considered the Deuter ACT 90+10 (or NOLS version) and MH BMG. The Deuters got some bad reviews for not being too durable and the MH got some bad reviews for comfort - don't know if this is true, but that's the impressions I got. However, I couldn't find any "bad" reviews for the Denali Pro - the only consistent downside was weight. However, as I soon confirmed on my own, this added weight is due to this packs ability to distribute and stabilize even very heavy loads. Think of it this way: If you're hauling 75lbs of gear, what's an extra couple of pounds of base-pack weight (negligible), especially if it makes that 75lbs feel like 25lbs?My first impressions of the pack when I received it: Wow, this thing is professional grade. The materials are all heavy duty, the stitching is ample and re-enforced where needed, the zippers, buckles, webbing, internal heavy mesh, etc are all "heavy duty". I suspect this thing will last a lifetime.Custom fitting the pack is fairly easy. Once you get the right hipbelts and shoulder straps, these attach quickly and easily. The shoulder straps can be attached in an upper or 1" lower position to further tune the pack to your torso (I chose the upper for my torso).My first trek was a day trip, only 9 miles with 45lbs with no issues. Subsequent treks, with more load (up to 75 lbs), and the pack still feels like it could carry more, and my body doesn't nearly get as fatigued or sore as with other packs. The pack feels very stable. I haven't used it on any extended mountaineering trips yet, but will come back to update after logging some more trips.