My experience with customer service from exo mtn gear: they responded to emails within a few hours and provided expert suggestions. I ended up ordering a K4 frame with 5000 bag. Since I knew I would be hunting for the month of November, I asked that they delay shipping so that it would arrive the day I got back. They did. I decided to add a water bottle attachment and they added that to the order without having me pay separate shipping. They gave me a good military discount.
My experience with Kifaru: they sent me an email offering free shipping on my first order. I asked about a military discount and they gave me a code. When the Black Friday deal was announced for Ark frame and Hellbinder pack that included a free water bottle holder and two pouches, I ordered that. They charged me for shipping and did not include the gifts as they said that the same discount Exo had given me precluded the gifts or free shipping. I initially ordered a camp bag too, as it was advertised as 30% off, but they charged me the full price. I asked customer service why, and they said only certain colors were discounted, unlike the email they sent me. I cancelled that part of the order and reordered the color on sale. They charged separate shipping they said that although nothing had been shipped, they couldn't combine orders unless they were ordered at the same time. All this took five emails and two escalations to senior support. They refused to combine the shipments, so I cancelled all the orders.
I do not know which backpack would be better, but I am certain which company I would like to support. One is owned by hunters. The other is owned by someone who bought a hospital.