My experience with SONY DL is that they work fine. A bunch came with the drive so they were the first I used and for couple years they all were fine. Then one day they stopped being recognized when burning. Switched to Memorex for a time, then they failed. Tried a couple other brands as well. Turns out it was not a disc issue it was the drive getting dusty. Once blown out everything worked as usual. Have mailed and handed out over 100 DL discs and haven't gotten back any 'it doesn't play anywhere' comments. But these experiences are relatively meaningless since i'm only certain of 10% of people who didn't have a problem, the other 90% never heard back from!

(and i see i've told this story earlier in the thread, knew it sounded familiar...)