I don't mind systemd and I've administered a lot of stuff with it at this point, well beyond just start/stopping services -- I've written plenty of unit files, written drop-in unit file overrides, written timer units, written auto-mount units, looked at startup timing profiles, debugged issues using journalctl, etc.

If I had to guess, it's probably because I've never ran into any of the weird systemd problems that I see people report sometimes. For me, it's always pretty much just worked, and more often than not it natively has the functionality that I want.

My largest complaint is that I have to bounce across several manpages to write a comprehensive unit file.