It typically has less to do with performance or stability than with ease of use. While Linux is piling on features, BSD focuses on clean design and quality of code and documentation. Linux is "do it now," BSD is "do it right."
I hate to press you on this point -- the wreckage of many a
flame war has barely had time to grow moss -- but can you point
to a specific feature? I assume you mean OS level features --
system calls and such.
