I hate to disagree with Nilbog because I'm sure he knows way more than I do. Still I think his prejudice against TDK (or non-Sony branded MD's) is not based on factual information but rather on preference. If you read other threads on this bulletin board, you will not find many comments that provide empirical data to support that Sony is a superior brand. Instead, you will find a few comments that imply that the Sony branded disks appear to be from the same mold as (or in other words, completely identical to) TDK disks.
As I have stated before, Sony has not convincingly produced any products whose quality is beyond question. I have had several Sony products over the years, including their 4 track MD recorder, TVs, stereo amplifiers, CD players and the like. My experience with Sony products has been that while they are truly an innovative company, their QC leaves a lot to be desired.
My own opinion is that you will find nothing inferior with the TDK disks. I have 20 plus MD data disks and 18 of them are TDK. I cannot recall any problems with my MD-8 that were related to poor quality disks from TDK.
Just an alternative thought to what has already been posed.
Hope you were able to find a good deal on disks!
Best regards,
DHN