I am using NixOS and have used Arch before. Its great. No dependency hell, superb config management (with home manager) and builtin rollbacks. But the nix language is somewhat arcane. Error messages are only somewhat helpful and docs are really lacking. NixOS also uses quite the amount of disk space in its store. Would only recommend NixOS if youre a resourceful programmer (or not)

PS. Ive never had arch break any drivers on me, or any upgrade failing (unless a package itself is borked, but they usually put out posts for this). But my systems all amd, ymmv

Except that the instances are usually full. There is hope, but not much

This very much. I used to have lots of unchecked config and state files everywhere on Arch. Now everything is checked in and wiped on boot so if something breaks after a reboot i know what broke.

Like how the opengl rendering did due to nixpkgs version differences