Speaking as a Linux user/developer who hasn't touched any BSD in a long, long time, I can perfectly understand why many people would prefer FreeBSD. Not dissing on Linux (it's still my personal favorite, and Debian is my goto for everything), but it's always good to have choices; to each their own. From what I understand, whilst Linux has the drivers and software, most server setups could be easily swapped out for FreeBSD (drivers are usually not problems on servers, and most server software you'd want to run is open source and already ported and packaged), plus FreeBSD has some things still not in Linux that a smart admin could use to give their startup an edge.