They skipped NixOS, tried it after another breakage in Arch around a year and a half ago, the AUR was nice, with it infinite packages, but I'm very happy I moved. Once you have a complex setup, or (inclusive) more then one device, NixOS gives a lot of benefits. The power to program your device and it's configuration, to sync those changes with git, keep backups, rollback (form NixOS updates and configuration changes). It saved me a lot of time when my computer died (hardware failure), it took about 10 minutes to reconfigure a new one to my liking. I'm eyeing for remote management of computers used by unsophisticated (computing wise) friends that want Linux but need my help from time to time. It will allow me to give them "apply remote changes" and "reverse changes" buttons, so they can just ask for the change and I can create it for them without fear of breakage.