As an upside OpenRC is simpler and even more configurable than systemd whilst being almost as fast, having had dependency based boot since before systemd was conceived.
Wait does it mean other init systems did not have dependency based boot? I have always been a Gentoo user so always used OpenRC, if that's the case it explains why I never understood why systemd was so "revolutionary".
I do find it harder to configure and understand than OpenRC, after I edit some configurations I can just restart the service and it's working, with systemd I have to run more than one command and they are not intuitive at all.
There have been quite a few. But until Ubuntu introduced Upstart, and i am sure someone will claim it was not dependency based, few if any reached mainstream usage. Keep in mind that RHEL6 actually use Upstart as pid1, but you would not guess it as Upstart deals with sysv rc "just fine".
Thing is that systemd is lead by some of the most myopic developers in the Linux community. If is not in use by RHEL or Fedora it does not exist. End result is a litany of NIH projects that could have been avoided had they looked around just a little bit.
Upstart is not actually dependency based, it's event based. Which is similar but not exactly the same.
It's worth mentioning that the -idea- of systemd if limited to replacing pid 1 with a more reasonable system and something akin to unit files is an excellent one and would be an improvement on OpenRC. Sadly as many have noted systemd come with a lot of very very bad side effects..
I do have polkit installed, there is an use flag "systemd" that I have disabled and so far I had no problems, it keeps systemd away from my system, and everything works.