This is one of the finest Late Beethoven performances I've heard. Of more than ten recordings of Op. 111, (including renditions by Schnabel, Horszowski, Serkin, Kempff, Backhaus, Arrau, Badura-Skoda, Michaelangeli), the Kovacevich is
my clear favorite. The first movement is solid, granitic, powerful, sonorous, and the technical demands are well met. The Arietta is the real jewel on this disk, however. Overall, this interpretation exceeds even the wonderful 1940's Schnabel recording that was released in Phillips Great Pianists series. It's near-impossible to describe this music, so I won't try. But this is a great way to hear it.
The other sonatas on this disk also are wonderfully performed. The first mov't of Op. 101 is an especially lyrical, sensitive, well-balanced interpretation. But I still enjoy Serkin's more granitic approach, and Kempff's sparkling performance of Op. 101 as well.