I use OpenBSD at home, among other OSs, and Centos (a Linux flavour) at work. OpenBSD has a reputation for good security, but what I particularly appreciate about it is the quality of the documentation. IMHO, it’s the best there is. The man pages are invariably concise but complete, and almost always have examples. A good Centos man page will sometimes be well written, but examples are rare.
It’s not uncommon to install a Centos package and find there is no documentation. Sometimes, packages install documentation somewhere entirely random. For example, I recently installed BackupPC: the documents had been concealed somewhere non-obvious, and the installation gave no pointers. At the very least, an OpenBSD package installation will tell you where the documentation can be found.
Also, I find Open BSD configuration files to be more rationally laid out, although that might simply be me having got using to the OS.
Linux clearly has its dominant place, and is the best choice for a number of tasks, but, if I were forced to choose one, I’d go OpenBSD.
Originally posted on quora.