brand means mothing really.
If you buy Sony there is no qurantee that you will get a real Sony disc.
For example I have few Sony disc made by Panasonic, or few Maxell made by Verbatim, or Memorex made by Ritek etc...
so far the safest bet are Panasonic and TDK. All Panasonic and TDK disc I seen so far are real Panasonic and TDK disc made in japan.
Verbatim started using factories in Taiwan, these disc are mostly likely fine, but for same price or less you will be better off with Panasonic or TDK.
here is a good thread with examples
and what ever you do avoid media made in China