Long time Arch user here but I'm growing more interested in NixOS by the day. I'm mainly “utilitarian” in my OS choice and other things being equal, Arch's AUR packages is what keeps me using it.
How does the Nix ecosystem compare with AUR? Would you still recommend making the switch?
Nixpkgs itself is several times the size of the base Arch Linux package collection, and by ‘non-unique’ package count, Nixpkgs is also much larger than the AUR. In addition to Nixpkgs, you can find Nix packages in several community ‘overlays’ for Nixpkgs as well as Nix's own user repositories.
You can check to see whether everything you currently use/need is conveniently available for NixOS in a comprehensive-ish way through the combination of these two web search tools:
Fwiw, packaging most things for Nix is very easy. I left Arch in ~2010 because at the time the package management stack and default repos on Arch basically sucked compared to most distros I'd used and liked, and from then on I decided that if I wanted software that wasn't in my distro's repos I'd just package it myself. After taking a little time to learn the tools on whatever distro I was using, I never missed Arch or the AUR. Compared to other distros, packaging normal software from source is usually exceptionally easy on NixOS.
If I were you I'd just dive right in and hit Nix's channel on Matrix with the Nixpkgs manual in hand if I found something I wanted to use that wasn't already packaged. But you can fall back on the options outlined above.
Almost everything I used on Arch is available on NixOS. In fact, for a lot of software I was able to use a more advanced configuration because NixOS makes it easier than Arch to set up.
I only ran into one hiccup: NixOS has an open pull request for supporting plymouth for silent boot with a LUKS encrypted drive. For now, I am stuck with an ugly password prompt when I turn my computer on.
It should be pointed out that you can install the nix package manager in Arch (or whatever other Linux, or macOS, etc.), so you can try out nix's declarative package management without actually switching to NixOS.
I tried this on my previous laptop and ran into a number of issues once I tried to install anything with a GUI. It's fine for shells and CLI tools though. I migrated some configs over to a Nix configs under Arch, and while it was a pain to initially set up NixOS (unfamilarity), it's a lot easier doing everything else now.
Yeah, I’m not sure how up-to-date my knowledge is, but opengl and the like are exceptions to the usual deterministic handling of dependencies on non-NixOS distros (not because it is unable to do so, I think it is mainly to avoid storing everything n-times with nvidia/amd), and one has to specify them. It was quite a time I ran nix on a non-nixos distro but there is this tool https://github.com/guibou/nixGL that meant to solve the issue of graphical programs.
How does the Nix ecosystem compare with AUR? Would you still recommend making the switch?