I'm using Guix which uses Shepherd. It's really nice if you're comfortable with Lisp or Scheme/Guile to be specific.

To people wanting to move away from SystemD though, I'm personally partial to OpenRC. It's not very complex at all. As for distros that use it, Void Linux comes to mind. I was also pretty comfortable daily driving Alpine Linux for a while. Both are very much "get out of the way and let me work" distros in my eyes.