All just my personal opinion
Comparing recordings with the following artists: Casals/Horszowski (1939), Fournier/Schnabel (1948), Fournier/Gulda (1959), Fournier/Kempff (1965), Harrell/Ashkenazy (1987), Isserlis/Levin (2012), Maisky/Argerich (1991), Perényi/Schiff (2004),
Queyras/Melnikov (2013), Rostropovich/Richter (1962), Wispelwey/Komen (1991), Wispelwey/Lazić (2004)
Comparing recordings with the following artists: Casals/Schulhof (1930), Fournier/Schnabel (1947), Fournier/Gulda (1959), Fournier/Kempff (1965), Harrell/Ashkenazy (1987), Isserlis/Levin (2012), Maisky/Argerich (1993), Perényi/Schiff (2004),
Queyras/Melnikov (2013), Rostropovich/Richter (1961), Wispelwey/Komen (1991), Wispelwey/Lazić (2004)
Franz Schubert’s Four Impromptus op.90 (D.899), in interpretations by Arthur Rubinstein (1928, 1949, 1950, 1958, 1961) and András Schiff (1990)
Beethoven: Piano Sonata No.32 in C minor, op.111 — Comparing recordings with the following artists: Wilhelm Backhaus (1961), Paul Badura-Skoda (1969), Daniel Barenboim (1984), Ronald Brautigam (2008), Friedrich Gulda (1967), Julius Katchen (1968), Wilhelm Kempff (1964), Igor Levit (2013), Maurizio Pollini (1976), András Schiff (2012), Artur Schnabel (1935)
Beethoven: Piano Sonatas — summary for comparisons of recordings, involving the following artists: Wilhelm Backhaus, Paul Badura-Skoda, Daniel Barenboim, Ronald Brautigam, Edwin Fischer, Emil Gilels, Friedrich Gulda, Clara Haskil, Jos van Immerseel, Julius Katchen, Wilhelm Kempff, Igor Levit, Mikhail Pletnev, Maurizio Pollini, Svjatoslav Richter, Arthur Rubinstein, András Schiff, Artur Schnabel, Mélodie Zhao
Beethoven: 6 Variations on an Original Theme, WoO 77 — Ronald Brautigam (2010, fortepiano), Olli Mustonen (1995); Beethoven: Allegretto in B minor, WoO 61 — Ronald Brautigam (2010, fortepiano); Beethoven: 6 Ecossaises, WoO 83 — Alfred Brendel (1985)