After two months using FreeBSD (TrueOS) exclusively it was apparent that I would rather live with systemd and even btrfs than lose the benefits of using NixOS.
My natural preference would be Guix instead but right now I’m unable to be 100% productive with it due to lack of some packages, services and filesystems.
So I have been running NixOS again and took a chance with btrfs. And though all my bits are still there its functionality was not interesting over ZFS so I will come back to a ZFS NixOS setup for my next laptop.
I will do a NixOS presentation on December’s sudoersbcn Meetup so if you’re curious drop by.