I had both an Exos 46 and 58. Great in heat; I think they're brilliant packs. But I couldn't make them fit me. I had some of the previously described problems with keeping weight off my shoulders. I would tighten the belt until I thought the skinny thing would cut me in two, and still no go. Maybe my waist is too big (36"), sold the 58 to a skinny buddy, he thinks it's great . My Gossamer Gear Mariposa is a dream compared to the 46. But I bought a ULA Circuit to get a little more durability. Gotta love those cottage industry guys, call with a question, they call your cell phone to answer.