SuperDrive is a DVD-RW as well
According to a MacinTouch reader, Apple's SuperDrive can also be used to write DVD-RW media:
At last, Data back up on SuperDrives. I just received my first pack of DVD-RW disks to try on my G4 733 and I have to report they write data like a hot knife through a butter, a whole 4.7 gigs no proble
A nice added feature for the $250 option (above a DVD/CD-R) on the new PowerMacs.