FreeBSD has also some advantages. The major disadvantage I see is that there is less adoption, thus less possibility to get help with the various issues endusers do face.
If you're not an average endusers, and you don't need to support average endusers with all their gazillion hardware and software needs, that's not an issue, of course.
Also, note they because FreeBSD is orders of magnitude less bloated and organizationally convoluted, it’s easier to implement functionality you need.