I added the repos to my existing arch install sometime last year I think. It's pretty seamless in that regard, I think I only ran into a mirror sync issue once, and it was resolved a few hours later.
My CPU supports the v4 packages, but I'm not really sure how much benefit there is for most things. (And things like tf/torch aren't coming from the repos anyways.)
I also use their kernel. I can feel a difference between stock and zen or stock and cachyos, but I don't think I'd be able to tell zen and cachyos apart tbh.
I definitely wouldn't switch distros for it, but since it's a trivial, drop in repo, I'll keep using it.
Adding another organization isn't ideal trust-wise of course.
https://xkcd.com/2929/