I've use a Jam2 on occasion, just because I hike in a pretty rocky part of the world. Mine has held up fine, and I'm pleased with how it carries. I just replaced the foam pad in it with the blue foam CCF pad from Walmart, just to see what it's like. I also have a Mariposa, and I was happy with how it carried. Just sent it back for the retrofit with the aluminum stays, much nicer now. Can't really see a need for load lifters with the new curve; sure don't need them if you don't overload it. And FYI, the Gorilla is identical to the Miniposa, just a tougher, heavier fabric, and aluminum stays.