Update: Got the K4 and like it, but the 23.5" frame is just too short. Now I have to send it back for a 25", and shipping sure isn't cheap. So far I like it better than the Kuiu under load; it doesn't sway as much and the hip belt is superior. However, the Kuiu is still far more comfortable when under 20lbs and the bag layout is much better for day trips, just not overnight trips. I probably just need more time for the K4 lumbar pad to break in, but with only 16 days until Elk opens and having to swap frames, I'm not sure if I'll have time to figure that out before getting on the mountain. Thanks again everyone for your comments.