I use Nix on an ARM single-board computer to host a personal Matrix homeserver (and a bunch of bridges), and I absolutely love it. It's invaluable to have a reproducible specification of the whole system, including custom software to build, in a single place.
That being said, for day to day stuff Arch (and Nix standalone) works well enough for me, to be weary of switching my daily driver PC to Nix, out of the fear of dealing with unforeseen issues and maybe encountering less well maintained packages (there's always something broken on Nix unstable, but maybe it's not an issue for more popular stuff). So I'm sticking to Arch for non-servers for now.
That being said, for day to day stuff Arch (and Nix standalone) works well enough for me, to be weary of switching my daily driver PC to Nix, out of the fear of dealing with unforeseen issues and maybe encountering less well maintained packages (there's always something broken on Nix unstable, but maybe it's not an issue for more popular stuff). So I'm sticking to Arch for non-servers for now.