Running it for years already. Recently my hard drive failed and with my data on a separate drive the replacement of the failing drive and subsequent #NixOS reinstallation was easy.

All the configuration is in configuration.nix, with low-level details abstracted away. Generations, roll-backs, nix-shell -p somepackage to try out something without actualiy installing it, etc.

Found out I cannot go back to regular #Linux (have tried but never got past a live boot environment because it soon became apparent what I would be missing).