Rating: 4 / 5
Based upon reading the previous reviews, I'm going to have to give this pack another look.
It was, for a very short time, quite a while ago, one step in my voyage "towards the light" (to quote GVP).
At that time, its volume was too small for my kit for anything but an extended day hike. I generally, even on day hikes, carry pretty much a full kit (sans extra food - just day hike/energy no-cook foodstuffs), both for conditioning and to make sure that i can weather a night out waiting for rescue if i sprain an ankle and can't ambulatory out under my own motor.
Given its intent, i had no gripes about the hip-belt. The shoulder straps, as others have already noted, are surprisingly flimsy. If i hadn't purchased it on the web, and had seen it first hand, i probably would not have purchased it. However, having said that, i was surprised that those shoulder straps could handle the 18-22lb load i was putting into the pack at the time. The hip-belt must have worked better than I thought it would.
It's worth another look, since there are some trails/places i won't take a G5 or G6 due to overgrowth or sqeezing between rocks which can damage the Spinnaker fabric those packs are made out of. But the Jam's fabric is much more robust (dyneema rip, IIRC). My curent UL kit and 3day food should fit fine.
To the best of my recollection, i'd give this pack a 3.0 based upon how i used it. Now, i would imagine, the score would be higher, maybe 3.5-4.0 - hence, my current score. Giving the Jam a 3.0, at this time, would probably not be accurate since it can now, for me, function as more than a day pack, or could more easily handle a typical 2-3day trek load/volume-of-gear, or could more easily, if used on a conditioning day hike with a faster pace, handle a slightly lighter 10-15lb load.