The funny thing is I've encountered more users that think OpenBSD uses ZFS rather than FFS, and more likely than not have never heard of FFS. I think it comes from some people referring to FreeBSD simply as BSD and saying "BSD supports ZFS" which leads to generalizations.
I use OpenBSD and just accepted the default filesystem when installing, and paid no mind to it. If you asked me which filesystem I was using, I wouldn't know without looking up.