It is quite basic still and historically had some problems with reboots, but lately it has gained a lot of attention and bug fixes. I have no experience of runnit, compared to systemd is leaner but in my experience there's no big feature lacking
I miss 'systemctl poweroff' (haven't learned the new herd equivalent); also, 'herd --help' doesn't really give any useful information and only lists a few things you can do... Have to really dig into the documentation (someday). Also, the 'shutdown' syntax has changed... Otherwise, most stuff has gone well