This blog by Vermaden is probably one of the most cited in the FreeBSD community when someone in a forum/subreddit asks why FreeBSD. I think it does a good job encapsulating the reasons one would choose FreeBSD over Linux or other OS’s.
I’ve become more partial to the *BSD’s in the past couple of years and respect what each one brings. I do daily drive Debian tho ;)
here is a discussion on Reddit about OpenBSD:
https://www.reddit.com/r/openbsd/comments/6qd3pf/openbsd_proprietary_components/