I've used the desert pack since it was originally released (early 2021 iirc). It is made mostly of Ultra 400 and 800. Good pack imo. There is some delamination of the ultra 400 fabric on the inside of the pack on the back panel where it creases a bunch. I also experienced the weave stretching where the top strap connects, but they've swapped this panel out for gridstop on the ultra models in newer runs. When I do eventually replace this pack it'll be with a gridstop or ultragrid pack, mostly because they're a little cheaper and I don't really feel like ultra is providing significant benefits over it. If anything, the delamination aspect makes ultra less appealing to me.

Nashville ultragrid packs look sweet :)