Yeah, configuring systemd with Nix changed it from annoyance to a pleasure for me. Instead of fiddling with a bunch of random .service files, you can just do everything in a nix config and have them generated for you. Complex systems involving a bunch of units (services, timers, paths, whatever) can all be in one single place--alongside the service config. You can easily share defaults between units.
It's so much nicer than doing it ad-hoc.