I tried nix on Ubuntu recently so that I could get an up-to-date, non-snap emacs (if you already think emacs is slow to load, you should see it as a snap), and the resulting build was giving me all kinds of issues, even with just the vanilla config. I tried one other package and had issues there as well. I ended up just compiling both from source and they worked perfectly.

Is there anything special about getting nix working well with other package managers? I'll be honest, the main thing keeping me from digging into it further are the docs and the syntax. I can never tell if I'm reading about nix-the-package-manager, nix-the-language, or nix-the-operating-system; and looking at the syntax makes me understand what most programmers feel when they look at lisp.