SuperSync is the most obtuse, confusing and flaky piece of software I have wasted twenty bucks on in recent memory. I wish I had spent that money on eight different iPhone fart apps instead. The UI is completely obtuse. It's a continuous exercise in, "why is that still grayed out??" and "seriously, is there no way to get a list of these differences??" and "CRC error again, you must be shitting me."

Before I'm forced to write my own using rsync and AppleScript, is there an iTunes-synchronization tool that actually works?

Update: Ok, fine, god dammit, I wrote my own.