I've used and purchased another relatively obscure DVD copy program for OS X (plainly named "DVD Copy") and it worked fine with 95% of the DVD's I copied. Today, though, it would not work on 2 DVD's: one probably had Sony ARccOS and the other had region code protection. Fast DVD Copy 4, thankfuly, quickly and accurately copied both of those DVD's. I'm using version the latest version (4.1) on a Mac Pro with 2 internal superdrives running Leopard. I would give this app 5 stars if weren't for the shamefully high price. 5 stars for the app, 1 star for the insane price, so it only gets 3 stars.