and you take a performance hit at import time to compute the hash.

And it's very noticeable. I have all my tunes in a distributed filesystem, and I figured... eh, sucking them across a wireless network and then cramming them back is sucking like usual. So I switched to wired, and it was still slower than before (usually I remember to just do it wired right along).

Given that I usually batch imports and then go to sleep, I'll probably disable it, but it's a neat idea.