There already has several opinions about the same as mine, which therefore makes it probably unnecessary, but I can not resist the urge to share my discovery of this interpretation. I know those of Brendel, Arrau, Gulda, Schnabel's last sonatas by Pollini, and some others, but, despite having always heard that Nat, I did not know, probably also a bit concerned in respect of mono recordings of the 50s ... And what I discovered is amazing finesse, dosage, shades, intelligence, elegance, clarity etc, etc ... I would be tempted multiply laudatory adjectives. It is beautiful and gives the impression of having fallen on LA version of the Beethoven sonatas. Yet I keep well to declare authoritatively, because this kind of charts makes little sense, but what I can say is that it is sovereign, obvious, and is among the major integrals. As for the sound, it is quite remarkable little or no wind, full sound, dull, fleshy who has almost as only wrong than being single, which hardly matters. Of course, there still has some audible defects, age means, but the music is there, listening and without having to disregard the years ... A monument of Beethoven no amateur should not ignore ...
Precision finally: my appreciation of the sound quality is made from the edition Yves NAT its 1930-1956 records with more than justifies the purchase price, and allows you to hear Nat with as much pleasure in Schumann, with same qualities of interpretation, but also Schubert, Chopin and Brahms ...