Nix-Darwin and/or Home Manager on macOS can provide a nice, slow way to transition into the Nix world as well, for folks who are hesitant to jump in with NixOS

Nix-Darwin and/or Home Manager on macOS can provide a nice, slow way to transition into the Nix world as well, for folks who are hesitant to jump in with NixOS and like to have other options around. There's even a very nice Homebrew module for Nix-Darwin to let you manage Homebrew from Nix if you want to Nixify without giving up Homebrew! It doesn't feel nearly as 'safe' as NixOS, in that OS upgrades are less predictable and can break a lot of things (not limited to Nix). But all-in-all, it's really not bad, and for some use cases it might be better.