Was a big fan of another pack company since the early 90s, but when I wanted to update to a lighter and smaller pack, their 2800 size didn't fit in m or L and the lower back padding design caused nothing but pain. So I tryed on the Kestrel and Yes!! Instant comfort and fit and I didn't even dial it in yet. First outing was a two day hike on the AT In the Kittatinny mtns in nj. It held all my gear in comfort with room to spare so I felt good about choosing the 48 size. In the future I'm hoping to sqeeze in enough food for 4-5 day hike but that might be asking too much. I got the Osprey bladder to avoid any bladder bulge I have seen others comment her on. Excellent bladder even if a bit heavy. If I was to change anything about the pack it would be to eliminate the vert. zipper pockets in the main portion of the pack. these seem unneccessary, in fact, if some of the extras were eliminated and the pack was just a top loader and it helped lighten the pack I would put it at 5+ stars. What features sold me on this pack? shoulder strap adjustablity, wire in the frame giving light weight comfortable support, and packs solid quality construction.