reddit originally ran on FreeBSD. They switched to Linux before I got there for ease of administration. I wanted to switch it back to BSD, but never got around to it as it wasn't very high priority. I tried to switch again when we moved to Amazon, but sadly it wasn't an option so I went to Ubuntu instead.

I've always thought that BSD is superior from an admin perspective, as in it's easier to do it right and keep it solid.

I may be biased though as my first job was IT for a company that had BSD committers so everything we did was on BSD and I learned how to admin from arguably some of the best BSD admins in the world.