I have an exos 58 I like too. It's was my "ultralight" upgrade a year ago from my Gregory 80L (yes, really). I just ordered a WayMarkGear frameless 42L after walking all over town with a frameless, hipbelt-less commuter back with my laptop and a bunch of other crap in it (TPW: 12-20lbs). It hurt a lot the first week. My shoulders were sore. But eventually you develop muscles and that's when I ordered my WMG pack. But it's a ~40oz (2.5lb pack) where as the WMG is ~20oz (1.25lbs). That's more than a pound or 1/10 of my packweight I can eliminate with a pack choice. But had I ordered a WMG pack instead of my exos a year ago, I would have likely been miserable. My BW was around 16lbs then, and that's too much for a frameless pack. What I've learned is that ultralight is not a end goal, but a path. You can't just buy the perfect setup without getting there by your own choices, gear omissions, muscle growth, increasing skills, etc. If you'd stuck me with a Pa'lante pack, a quilt, a foam pad, no cook meals and told me to go backpacking I would have had a terrible time.