There are few system manager (single project or a mix of components) that use linux features efficiently and none have dev resource remotely comparable to systemd. That’s why in practice systemd is the best system layer implementation on gnu/linux. Android and chromeos userland (upstart derived) are not exactly (freedesktop) gnu/linux.
EDIT: the post ask which OS though. Including userland I like android a lot, but I would say illumos distros (OI currently). illumos has a system management similar to systemd (contracts in place of cgroups for example). Actually systemd was heavily inspired by SMF too.
There are few system manager (single project or a mix of components) that use linux features efficiently and none have dev resource remotely comparable to systemd. That’s why in practice systemd is the best system layer implementation on gnu/linux. Android and chromeos userland (upstart derived) are not exactly (freedesktop) gnu/linux.
EDIT: the post ask which OS though. Including userland I like android a lot, but I would say illumos distros (OI currently). illumos has a system management similar to systemd (contracts in place of cgroups for example). Actually systemd was heavily inspired by SMF too.