professional, store bought titles are pressed. A master is fabricated and the copies are physically pressed, not burned with light.
All the solutions consumers use, burn the media with lasers.
Frankly, after seeing photomicrographs of burned media, im very, very amazed that this process works at all, for any extended length of time. At least at the prices were paying for these burners. The pits created by the laser, are very messy.
im not surprised that i have a whole shelf of 'burned out' burners. My OEM optiarc just gave out 5 days ago. Errors reading, writing, hanging, crashing. Im not going to replace it. I put a IDE hard drive in the upper bay instead.
what can we expect for 30$ now? Plastic parts, gears and belts. In something that spins so fast and vibrates and gets vibrated by the rest of the machine.
my guess is that your drive is tired and dying.
my suggestion is to try your disks that fail in any other machine you can try. If they work in other peoples drive besides your macbook, then the culprit is your tired macpro drive. Then pull it.
my fiinal suggestion is to not depend on optical media (burned at least)