Anybody here have a Mac iPod? How does it handle playlist synchronisation?

My Ipod is a Mac one, and although I haven't tried adding m3u files to it using Xplay, if I drag-and-drop from my PC onto a playlist, it doesn't create a duplicate file if that same file is already on the Ipod somewhere else. (This makes it smarter than Emplode, not dumber.) If it's smart enough to do that for individual files, it's almost certainly smart enough to do it for playlists.

Peter