First, prospective buyers should know that while the amazon description lists only the D894 sonata, this 2-cd set also includes the D575 and D840 sonatas. Having said that, this set offers surprisingly disappointing playing from Richter, who was a great Schubertian. The first movement of the D894 sonata, which clocks in at 27 minutes, finds Richter stretching things beyond the breaking point (Brendel, Lupu and Zacharias, who take an entirely different view of things, turn in performances of 17 minutes each). Time almost stands still as the pianist serves up a statement that is just too subjective for my ears, and while the rest of the sonata is natural enough the whole thing sinks under the quicksand pace of the first movement.
Richter is much more natural sounding in the B major sonata D575, where he turns in a pretty good reading, but he reverts to ultra-slow motion in the first movement of the C major sonata (D840), known as "Relique." At 22:31 minutes, Richter is nearly 32% slower than Kempff who clocks in at 15:12, and moves at half the pace of Brendel, who plays this movement in 11 minutes and 36 seconds. I cite these timings not to suggest that these other pianists, who are also great Schubertians, are turning in high-voltage performances, but to illustrate that Richter is way off the mark. Richter also plays the unfinished third and fourth movements, which are typically omitted.
The liner notes don't tell us where or exactly when these recordings were made; the back of the case merely says "recordings made in 1979." All in all, these recordings are not representative of the Richter who turned in monumental Schubert readings for EMI (Schubert: 'Wanderer' Fantasy; Schumann: Fantasy & Papillons) or can be found in live performance (e.g. Richter in Hungary) among others.
For those looking for Schubert sonatas, I would recommend Brendel Schubert: Piano Works: Sonatas / Moments Musicaux / Impromptus / 'Wanderer' Fantasia or any of Kempff's performances followed by the fine EMI set from Zacharias (Schubert: Piano Sonatas). Five of the ten discs of Lupu's The Complete Decca Solo Recording are devoted to Schubert, and these too are very good.