I wouldn't lump Stone Glacier and Kifaru's packs in with the likes of the BL Sacrifice.
In my experience, durability is top notch with Stone Glacier and Kifaru. You could literally throw them off a cliff and down a mountain.
As an update to the topic,
Kifaru, Stone Glacier, and Paradox packs all have some really interesting pack designs coming out for 2014. The serious ultralight hunting backpack market has really taken off and competition is fierce!