Likes, that are maybe not integrated in NixOs ?: Scheme and elisp, are both lisp, and while It looks shit to start with, I'm coming around to it. Lisp is a clever language imho, so I like it as a configuration language (scheme). Emacs looks almost like a natural extension of Guix, and I'm finally starting playing with it. I feel that every little corner of the Guix have been designed for a purpose from the ground up. Repo is curated with floss goodness, and flatpak for the rest. I like the simplicity and 'order' of it all. Ah, the system installer is shaky, but..
I find guix as both a system and package manager easy and very powerful out of the box. I've had other systems/package managers for many years without using as many build-in features as now.
Besides std Guix, there are 2 spinoffs, pantherx that is supposed to be more enduser polished and rdb that are Guix+Emacs in a love relationship I think. Not sure, but you can check it out.
Maybe NixOS would do the same, but I've never been 'giddy' about a new distribution before, so I I'm just happy I found my new permanent distro. Not leaving.