I just made a post about my musing on NixOS so maybe read that? (here) Basically after the main learning curve it’s pretty easy to use.
I’m getting the hang of their package manager as well, so if need be I can make my own (Like I would for Arch. The AUR scares me from a security standpoint).
My main advice is to not go against the curve. If the manual says that NixOS does it that way, do it that way, because going against the grain is like going through a cheese grater in this OS.
Unlike Arch where you can do things as you want, in Nix you do things using Nix. You can almost always accomplish what you want, but it’s gotta be done the NixOS way. This is actually a benefit rather than a problem once you get used to it, because it starts becoming second nature, and it is extremely powerful.