This is a selling point I don’t often see people discussing but it has killed my need to swap distros… Possibly forever. I’ve been using it for a year now and have such a clean well organised config file. Version controlled, broken up into modules, with separate configurations for desktop laptop and server. Unlike any other distro, at any moment I can just hard reset to what that config describes. If I swap DEs, or python versions, or whatever else, the system no longer slowly builds up clutter and random arcane bugs and bloat. It feels like today my system is better, newer, and cleaner than when I started with it. And at any moment I can install my exact system down to every little detail on a new device. Nix is legendary for long term system maintenance.
That’s what I love about it, among all the other good things everyone talks about.