Don't get me wrong, I love Linux and have been using it since I was a kid. But, for what it's worth, here's my selling point:

Choose OpenBSD for your Unix needs. OpenBSD -- the world's simplest and most secure Unix-like OS. Creator of the world's most used SSH implementation OpenSSH, the world's most elegant firewall PF, the world's most elegant mail server OpenSMTPD, the OpenSSL rewrite LibreSSL, and the NTP rewrite OpenNTPD. OpenBSD -- the cleanest kernel, the cleanest userland and the cleanest configuration syntax.

You forgot cleanest code ;-)

http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/

Nitpick: LibreSSL is a fork/cleanup of OpenSSL, not a rewrite.

Given how involved that "cleanup" was, "rewrite" isn't entirely inaccurate ;)

Definitely not, curiosity is always important! I could mention the security focus and a bunch of other things but instead of going into another thread here explaining differences ( it looks like you already have a reply starting ), I'd suggest doing a search here on HN for OpenBSD. You'll find a ton of threads with discussions about the relative plusses and minuses.

There are several reasons why folks (myself included) prefer OpenBSD for a lot of server roles:

-- PF (which, in my system-administrating experience, is way nicer than any GNU/Linux firewall to date) is only available on BSD-derived systems (including OS X and - IIRC - Solaris), and originated on OpenBSD.

-- OpenBSD has a very strong security track record over the last 1 1/2 decades or so.

-- OpenBSD has been the source of a lot of really nice bits of software [0], and tends to be the first and preferred platform for quite a bit of that software. My own use cases revolve around PF, OpenSSH, tmux, httpd/relayd, spamd, and OpenSMTPD. httpd and relayd in particular are currently exclusive to OpenBSD last I checked.

This isn't to say that OpenBSD is right for everyone (notably, upgrading between releases and getting the latest patches for a given release can be... involved, to say the least), but there are certainly reasons to prefer it over GNU/Linux or the other BSDs.

Not to mention that some Linux-only software will happily run on the mainstream BSDs - OpenBSD included - thanks to a binary compatibility layer. Even things that rely heavily on Linuxisms - like Docker - can run on at least FreeBSD [1], and doing the same for OpenBSD, while probably more involved (OpenBSD notably prefers chroots over newfangled virtualization techniques like containers and jails; in the opinion of its authors and users, containers/jails/etc. only provide an illusion of isolation, and chroots provide equivalent functionality without dishonesty. While I don't entirely agree with this, I can see where the attitude comes from and understand the rationale.), might very well be possible sometime in the not-so-distant future.

[0]: https://en.wikipedia.org/wiki/OpenBSD#OpenBSD_component_proj...

OpenBSD is an really polished operating system built to a much higher, tighter standard than Linux and the GNU libraries are. I used it right up until "cloud computing", and then for economic reasons needed to use Linux instead.

The biggest problem with OpenBSD has been lack of support for hardware and virtualization, though a lot of the reason for this has been the OpenBSD team's own hostility towards virtualization. I get their reasoning (virtualization is a security issue), but the economic consequences have been devastating to their userbase.

The cost difference and ability to run on cheaper hardware was a big reason Linux won out over Windows. It's important to make operating systems accessible to everyone, even those that can't afford full dedicated servers.

"The biggest problem with OpenBSD has been lack of support for hardware and virtualization, though a lot of the reason for this has been the OpenBSD team's own hostility towards virtualization. I get their reasoning (virtualization is a security issue), but the economic consequences have been devastating to their user base."

If you watch the the ruBSD 2013 interview video with Theo de Raadt[1] at the 6:36, he states that they should take a shot at dealing with modern x86 VMs. That gives me quite a bit of hope along with the work on vmware related drivers in each release.

I use VMware at work, seems to do ok.

1) https://www.youtube.com/watch?v=OXS8ljif9b8

consistency and cleanliness. man pages are a dream, documentation solid and up to date. you can get things done and focus on what you want to accomplish, not what is getting in your way.