I've distro hopped from Debian, to NixOS, to Arch Linux. The neat thing about NixOS is that 99% of the system and user configuration was spread out across a handful of manageable files. And it was only multiple files because I modularized them; it could've been a single file. Localizing the configuration made it easy to wrap my brain around it.
I've lost track of what I've configured on Arch. I could've been more diligent and kept track but NixOS is more conducive to that from the getgo.
Another neat thing is that nixpkgs (the NixOS package repository) has everything, close enough for me anyway. In one place. I'm already relying on the AUR (a separate repo from the core Arch ones) and all that entails. NixOS (nixos-unstable) is also more bleeding edge than Arch if you're into that sort of thing (I am).
The entirety of your configuration being in one (esoteric, but simple) language was also neat
It wasn't without its downsides but I had fun with it. I totally get the hype.
I've been using Linux for years and years. I get the subjective sense it is a system built by engineers for engineers. I can examine, poke, prod, and break every aspect of the system. I consider that a bonus and it's how I learn about computers.
I can fly through the system with my terminal
Etc
Edit: Centralized software package and dependency management is awesome