I also have had both and can not say one wins hands down over the other.
It really depends on what your priorities are. Some of the arguments seem out of place. Both are modular, both have a robust load-shelf, especially if you have the new-gen KUIU. The current-gen holds much more weight on your hips and is a noticeable upgrade in the suspension system.
I find the fit a bit better on my KUIU, find things like the Kifaru Gun Barrer worth the extra weight over the KUIU offerings. BUT I am a 100% weight weenie. I also use packs like Zpacks and find them great for the load I will put in them. I am NOT an over-packer, be it at a match or hunting and scouting. For me, access to pockets and lowest base weight does play a role. No dought that the KUIU is more robust than my 21oz 60L ARCA ZIP, and less robust than my Kifaru was. All three are amazing for what they do, and each is best in the intended class.
With all the things we need to be honest with our needs. Are we a monster and will haul 200LBS of meat off the hill, many many times a year or maybe once a year? Do I drag my pack, rough on gear, or more mindful? It's just like getting a
uber light 300WM to hunt deer, just because someday you might hunt a sheep or a moose. When in reality, you're handicapped for the majority of your shots. You need two guns.
In my case, I am not a monster hauling dozens of Elk out a year. The majority of the time I use my hunting pack I am scouting or hunting pigs, so I am defaulting to the lighter packs that have good airflow, especially across my back.
BTW I do not have the legs to carry more than what comfortably fits inside the
new-gen suspension and load shelf. Here I am getting back after descending from the snow, with a
rear quarter and front shoulder of an ELK. The picture makes it look smaller than the quarters where. The weight was comfortable on my hips,
but over 100LBS was killing my legs.
Below is my Son with just one rear quarter and the load shelf without the pack attached. He was using the
older gen suspension and didn't carry the load as well on the hips, in my opinion.
If you pick the correct pack for your use, you can not go wrong with either brand.
Edited to add- opps I was writing just as the op posted again.
