Starch Linux seems fairly similar to Alpine Linux.
- Both uses OpenRC
- Starch uses musl, Alpine uses uClibc
- Starch uses pacman, Alpine uses apk-tools (which has some similar things as pacman - but is way faster)
- Starch uses BSD userland, Alpine uses busybox.
Since it is based on OpenBSD I'd assume there are some interest in security. I don't know if Starch has some kernel hardening but Alpine Linux uses Grsecurity in the default kernel.
Alpine Linux seems to be much more mature though and have some support for desktop stuff like XFCE, firefox and similar.