I dabbled a little with Nixos a while back (e.g. I think I reported the bug that broke the entire point of /etc/os-release for chroots, as well as commented on how to do a container install from scratch at a point when nobody documented it), but there were 3 things that really pushed me away:

  1. Nix has clear advantages for *deployment* (including end-user deployment) but really gets in the way for new *development*. Maybe flakes fix this? Maybe not though.
  2. The "Nix on other Linux" install scripts were hostile in attacking startup scripts, rather than allowing opt-in isolation.
  3. The Nix language (and library?) is not sane. Nobody actually understands it, only copy-pastes pieces of existing package scripts and hopes the changes work.