I didn't believe rdgrimes at first when he said that Ricoh media is very variable. Well, I believe him now! Here are two burns on Ricoh media...
Same burning software.
Same data size (well, almost the same).
Same burning procedure.
Same burning speed (8x).
Same brand (Fuji).
Same media type (RICOHJPNR01).
Same source (bestbuy.com).
Same "made-in" (Taiwan)
Did I miss anything in this list?
The first burn was done on a disc from an old batch of media that I could a few months ago. The next burn was done on a new batch that I just got recently.
As you can see, while the first burn was perfect, the 2nd burn was a complete coaster (so far, about half the discs I've burned from this 2nd batch have coastered). (Note that the KProbe scan for the 2nd disc is very short; I cancelled the scan after about 27%, around 1 GB--shortly after the 6x->8x jump point in the burn)