Kifaru ranger green looks slightly different than Exo on these examples of 357 mag and K4. I prefer the Kifaru shade if I was picking fabric but they both look good. It looks a bit more obvious in different lighting.
It could be as simple as a change in the outer coating and not the full layup of the material. The textured matte finish could reduce the possibility of squeaking. It's also much less reflective than a gloss coating.
Long time lurker here that just got my ARK frame last week. Great looking piece of equipment. I haven't used it yet because I'm waiting to see if there's new larger bags to match it with. However, I looked it over and don't see any gouge marks. Also no wear on the strap fabric from the frame. I...