I'm unaware of any Linux distribution using SMF. If there was, I would have been running it. I didn't really like pfexec (it felt bolted on and not quite there yet), and I really really hated ZFS (and still do), but SMF made Solaris administration a joy.

I don't think any distribution was using runit before systemd, but it was available in Gentoo as a sysvinit replacement and ISTR it was used in the Rails community for supervising Unicorn.