Except the first sentence, I wasn't talking about linux. never said that one of the BSDs are a better server because I have the coherence that a tool fits the job and not the other way ... and that includes the operating system itself.Why would *BSD be a better server than Linux?
In my own experience and taste, I found that the features of the system are a big PLUS on certain situations ... (ZFS, DTrace, Jails, pf, resource containers, the layout of the base system and ports, etc etc etc)
Which filesystems are you comparing ?*BSD might be better server than Linux, because it's more careful with your data ... It doesn't risk for better performance.