I have the VOX set, and I enjoy it tremendously.  Anyone who considers
historically important performances has to acquiesce some sound quality.
Having set that, the quality is not objectionable.  Hey, they didn't
exactly have DAT machines lying around in '62.  I think the casual, or
even devout, Beethoven fan might find some of Brendel's interpretations
"dry." Portions of the "Moonlight" sontata, and a few of the other
"masterpieces" fall into this category.  I think the Brendel set makes
a nice complete collection that could easily be supplemented by the
outstanding performances of some of the great works by the likes of
Ashkenazy, Gilels, and others.  Good luck, and happy listening!

Jonathan Knapp