I'm on Arch too, but after installing NixOS on two side laptops I have, I kinda fell in love. I don't want to go through reconfiguring everything, but once this laptop dies, I'm going to switch.

Arch is really great, but using the system now for ~5 years I cannot remember where every configuration is, which packages are installed and why, and things just get messy. I'm sure that some issues the system has are do to things I screwed up along the way, and these will be solved if I just reinstall. But with NixOS it feels so easy to find what changes you've done to the system, to leave a comment saying why etc. It feels to me much more maintainable.

I used Arch for about a decade before trying out NixOS unstable channel. I won't be migrating back. Everything is much tighter and saner. Only complaint that I'd have is that the pull request merges and package builds lag behind a bit, but I've grown used to that. It's up-to-date enough.