I've had problems with my home CDR deck from time to time. You could try and Finalize the CDR and write the TOC, and for some reason, the data would not burn, leaving you with a coaster. If I missed 80min of a show because the TOC did not burn, I'd be mighty pissed.
I've heard this same problem can happen on MDs, but knock on wood, this has never happened. I've only had this problem with DATs once. My SCSI drive would not read one DAT I put in there because there were some funky IDs written at the start of the tape. It was an old tape, don't know if that was part of the problem.
DAT seems fine to me. I mean, doesn't one of these decks cost just as much as a used DAT?