9 lbs is far from best in terms of weight. Exo should be around 5/6. Same for stone glacier, mystery ranch, seek, kifaru. If you're able, definitely do a quick test run with 80 lbs (at least 50) prior to purchase. I was able to do so with mystery ranch, exo, and stone glacier. I liked how stone glacier and exo fit to the arch of my back better, though mystery ranch belt to frame connection felt more solid when not on back. On back they all felt solid. Didn't like how the waste belt and shoulder straps of mystery ranch hit me, I think due mostly to narrowness. And the "load shelf" setup didn't seem as simple or as independently supportive (you just sandwich meat between the bag and frame, didn't have an independent sling). With the exo, as I shifted and leaned while loaded down, the load seemed to be shifting around excessively. I found this to come from the harness to frame connection. They run a single big wrap of fabric around the frame, pulled as tight as they can, but not tight enough, and the harness connection is stitched to the face of that fabric. So, fabric stretches, and you can pull harness tight to you as much as you want, and load as tight to frame as much as you want, but frame will always slop a little off of harness. I also wasn't sure about the open top side pockets, figured they'd gather debris. With the Stone Glacier, harness to frame connection real solid. This is because their frame is not and independent "thing" wrapped in a single piece of fabric, but is constructed by way of a fabric sheet with narrow channels that 4 separate frame stays run into (2 vertical, 2 crossing on an x pattern). The pulls to attach the bag or meat to the frame also attach on the back side of the frame panel, so pulling bag or meat down tight would pull any loose fabric (though there isn't any after a summer of training and season of use) on the back of the frame tight. Don't know if that makes much sense, but long and short, no slopping around of the load as you shift side to side. I ended up going with the 6900 with the new x curve frame (older style frame is straight and definitely does not fit to curves of back). I really wanted to try kifaru before making a decision, but didn't have the opportunity. But, the perfection of the 6900 bag design, for my purposes, and the fact that kifaru has only reluctantly incorporated load shelfs (can't imagine something they didn't want to do is executed particularly well), made me feel more alright about not trying them out. No idea about seek packs, just always looked a little too traditional aluminum frame to me; and that's exactly what I was moving on from. Best you can do is go fishing across the West next spring and summer and stop by all their headquarters in the process!
