The thing is, eds, you can only predict burn quality when using media codes and not manufacturer name. TDK, Maxell, Memorex and others use a variety of different dyes. Some are top of the line and some are bottom feeders.
The DL TDK seems to be Ricoh code, and videohelp.com only has one review, but it's a good review:
The Memorex 16x seems to be one of four codes:
Of which, only the MCC04 is top quality.
The two Plextor users at videohelp.com seemed to think the Verbatim 16x -R was pretty good.
This thread really belongs in the media forum...