In addition to other answers, I think it's important to note that Nix is comparatively very small (but growing!). To that end, the Nixpkgs policies are still in

In addition to other answers, I think it's important to note that Nix is comparatively very small (but growing!). To that end, the Nixpkgs policies are still in flux and defined somewhat culturally (at least compared to older, larger distros). There's a release schedule for NixPkgs which is being continuously updated, you mostly subscribe to a fixed "channel" which gives you the default set of derivations. If you need something more fresh then you either modify a derivation yourself (hot-patching the distro) or pull something temporarily from master on NixPkgs. This is hugely facilitated by the way Nix allows you to install multiple package versions in parallel without conflict. Finally, Nix is still sometimes a bit of a research project. The "best" way to manage a distro that's being built using this technology is still being uncovered. For instance, there's an upcoming feature (flakes) which hopes to seriously change the way you talk about and consider versions of NixPkgs and NixOS. Using Nix definitely requires some patience with living on the edge of tech. It can be frustrating and less reliable than other repos due both to the bigger challenge of building a repo using Nix's technology and the smaller contributor base. That said, the returns on using this weird technology are really high. The short pitch is something like "zero runtime cost, highly repeatable Docker containers for everything". Of course, the technology works nothing like that, but it really hit some of the big position independence value props of Docker in a way that's lightweight enough to use it for everything.