I don't have much to disagree with there, only that any survey answer is the difference between complex things is going to be simplified. I'm thumb typing here and no one's paying me to write a book.

I will defend my "heaviness" argument, though. Sure, you can run OpenBSD on large hardware, but it's not going to be able to take advantage of it like FreeBSD can. Which makes sense if you think about it - FreeBSD optimizes for heavy workloads. Conversely, if you set up minimal installs, OpenBSD will be smaller. Again, that makes sense, since OpenBSD focuses on security over features (plus the only truly secure code is the code that doesn't exist). There's a lot of overlap in the middle, of course.

I wouldn't use OpenBSD for a NAS, and I wouldn't use FreeBSD for a diskless firewall. Not because they can't do those things - they just each have their strengths and weaknesses.