Age of the gear?
I've had two go out on me. Mostly after two years. Those that worked in the first place anyway. The one on my compaq presario desktop is the best one I've had to date. I'm not sure of it's specs (name / brand). But it's been a real work horse.
According to cdrecord -scanbus: DVD A DH16A1L - KH15
Which appears to be some sort of LiteOn drive. Litescribe, DVD dual layer (just now noticing that), and all that jazz. A lot of people looking for firmware on it, but I've had no issues in linux with this drive. A couple bad burns, but because I wasn't using -dvd-compat on video dvds. Otherwise I've burned hundreds of discs on this one drive.