I have set up my archlinux os in a weekend with btrfs snapshots and everything I need. About once a quarter I tinker with it for 30 minutes to either fix a broken update or do some custom solutions to minute problems. It has been running like this for 5years. And snapshots allow me to rollback any fuckups in 1 minute.
I tried to setup nixos twice, because I love the concept. Both times I tinkered with it for 1 to 2 weeks, had to take paid leave. At the end, some stuff still didn’t work as I wanted it to. Any customization that is not already natively implemented in nix is a huge pain in the ass to add. Things that would be a 5min config edit on arch took hours on nix to make them rEpRoDuCaBLe. I have experienced no additional benefit over btrfs snapshots.
Tldr: If I could pay somebody 100$ to set up nixos just the way I want it, I’d use it. But since I have to do it in my own free time, I won’t.