It's all about the extra pain. (or the lack thereof)

Never mind that nowadays we have the linux version of "all the world's a VAX" syndrome. Not every OS has utilities that obey all the occult incantations of the GNU versions…

I'd encourage every Linux developer to get a similar setup with a BSD version – or even just an older and/or different Linux distro.

Valgrind on Lion.

LXC (obviously).