I haven’t used the k3, but put a k3 belt on my k2 and assume it carries very similar to the k3
Some had problems with the k3 slipping, but for me personally, my k1, k2 with the k2 and k3 belt all carried weight well for me and none slipped… the difference for me vs my kifaru was load stability with really heavy loads, the kifaru was more stable with a lot of weight
That’s where k4 shines, it has the same stability for me, and that classic exo comfort both in hunting mode and with super heavy loads… prior to k4, I had a very hard time deciding a favorite between my exo (k2 with k3 belt) and my kifaru, it was a toss up… the exo was more comfortable in all scenarios and carried a heavy load comfortably, but I did like the locked into your back stability of the kifaru… now it’s a very easy decision, the k4 has it all for me… it’s comfortable in all scenarios, and when coming off the mountain heavy, you can lock in a heavy load and be super stable, which is nice navigating tough terrain or blowdown with a heavy load
I appreciate the thought they put into the k4, and makes me curious how they could possibly improve on the design, but I know in a few years they will, because that’s what they do.
Another very cool thing about the k4 is the lumbar pad doesn’t trap debris and wear my back raw (only pack I’ve used that it hasn’t been a problem ever) and this is the longest I’ve had a pack and not developed a squeak somewhere, and it’s been very wet and very dirty a lot of times, so that’s a good sign
My pack is one of my favorite possessions. Everyone has their own taste in packs, but for me, I currently have zero desire to try anything else, which is another first for me… I have also tried about everything I could minus stone, and at this point I don’t think I ever will