> if I attempted to re-install software with Guix in parallel, would that lead to namespace collisions?
It shouldn't. That's one thing Guix (and Nix) excel at: packages only refer to specific versions of their inputs, so you can even install multiple versions of the same package at once if you want.
In terms of Guix shadowing packages installed by Arch, you can put $HOME/.guix-profile either at the front or the end of your $PATH depending on whether you want to prioritize Guix or Arch packages. When I was getting my feet wet with Guix, I ran Guix on top of Gentoo (doing basically what you suggested, gradually shadowing Gentoo packages with Guix ones) for a few months without any significant problems.
Could I ask you to compare guix and portage? I'm not an expert in either, but it looks like guix provides very similar source builds with easier binary caching/substitution.
I can compare. Ebuilds are nothing in comparison, and guix is much more flexible. What portage has over guix is the wealth of premade packages (for now)
Here you go: https://guix.gnu.org/manual/en/html_node/Binary-Installation...
> if I attempted to re-install software with Guix in parallel, would that lead to namespace collisions?
It shouldn't. That's one thing Guix (and Nix) excel at: packages only refer to specific versions of their inputs, so you can even install multiple versions of the same package at once if you want.
In terms of Guix shadowing packages installed by Arch, you can put $HOME/.guix-profile either at the front or the end of your $PATH depending on whether you want to prioritize Guix or Arch packages. When I was getting my feet wet with Guix, I ran Guix on top of Gentoo (doing basically what you suggested, gradually shadowing Gentoo packages with Guix ones) for a few months without any significant problems.