I have been using NixOS for about a year now. My daily driver is a Mac Mini M4, which I manage with nix (the package manager). I also have several NixOS machines that host my homelab, and a NixOS cirtual machine that I have started to use as my own fully-customized development environment.

All that said, the majority of my time using Nix & NixOS has involved minimal exploration of modules. I relied heavily on the use of the usual suspects: home-manager for managing my user packages and dotfiles and nix-darwin for declarative management of my MacOS environment. I never found an ideal replacement for my Neovim configurations, so I relied on the trusty mkOutOfStoreSymlink.