I've been on NixOS for about a week now and I can say I've got access to pretty much all of the packages I was using on Arch just from nixpkgs. I even found it quite easy to package stuff myself!
I am only using them and they seem very kino. I don't do anything complex with them, but, I like that adding new repos is as simple as reponame.url = repourl and then you can use its stuff after adding it to your outputs
What resources would you recommend for a complete beginner that wants to learn NixOS? I've been using it for a few weeks now, but I want to actually learn it and use the power of the nix language