Advice regarding DVD-RAM Drives

For the last several years I have been backing up live concert recordings I have made to 4.7GB and 9.4 GB DVD-RAM disks. I am using a G4 with an internal Mat****a LF-D211A DVD-RAM Drive. At some point, over the last year, I was unable to read or write the disks in my library (rather extensive investment at this point.) The only major change to the system was adding OSX but maintained and have been able to easily launch OS 9.2 on another drive within the computer as well. I'm thinking that the DVD-RAM drive may have died of natural causes, but am wondering if anyone has had similar experiences with their drive suddenly not functioning. I was able to borrow a similar drive from a friend and was able to read and backup most of the 4.7GB disks to DVD-R. I have considered purchasing a newer DVD-RAM drive but don't know if this will solve my problem with reading the 9.4's. At this point, I would just like to recover the files from the DVD-RAMs and move them to DVD-R. Any suggestions from those of you who might have already experienced a similar issue? Any recommendations as to which later DVD-RAM drive model will interface easily with my G4 (gigabit ethernet dual 500 MHz)?