I'm having it show all media differences between machines. Only my Win7 machine has all iTunes media and that is backed up to an HP MediaCenter server.
Each of the others then just pull over the items each user wants on their machine. Have not had an issue with it yet including all the music I ripped from my own CDs, audible books, etc. You might note, I do not have any, what you might call illegal content, so whatever format any of that may be in, I will not have tried.