As a user though I have absolutely no idea what is going in with Apple syncing. My wife has an iphone / mac syncing explosion that I simply can't fix. I just don't have any idea where the data is or why everything is duplicated in her iphoto collection. Or what's going to happen in when you remove something from one place.
Most of all I cannot for the life of me explain to my wife why it is that when she lost her phone and restored a previous backup to a new one it DELETED ALL HER RECENT PHOTOS from off her mac without warning. Gone, forever. I watched it happen before my very eyes and it's made me want to never buy another apple product again.