We loaded these packs with loads ranging from 35 to 70 pounds for side-by-side comparisons. We hiked over snow, sand, mud, and ice. We took them on overnight trips and wrote detailed notes along the way. We carried each pack for a while, then switch with our buddies and climbing partners to get a variety of opinions about how each pack felt. We even hosed them down to test water resistance.
We carefully took into account each pack's features and compared them with its weight and usefulness. Most importantly, we took them out on real-world trips, lived out of them, and critically assessed them along the way.