All just my personal opinion
Beethoven: Symphony No.4 in B♭ major, op.60 — comparing recordings with the following artists: Bernstein/New York Philharmonic (1962), Bernstein/Vienna Philharmonic (1978), Böhm (1972), Dausgaard (2000), Furtwängler/Vienna Philharmonic (1953), Hogwood (1986), Klemperer (1957), Norrington/RSO Stuttgart (2002), Toscanini (1951), Walter/New York Philharmonic (1952), Walter/Columbia Symphony Orchestra (1961), Zinman (1998)
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: Piano Sonata No.22 in F major, op.54 — comparing recordings with the following artists: Wilhelm Backhaus (1969), Paul Badura-Skoda (1969), Daniel Barenboim (1984), Ronald Brautigam (2007), Friedrich Gulda (1967), Maurizio Pollini (2003), Artur Schnabel (1935)
Beethoven: Piano Sonata No.15 in D major, op.28, “Pastoral” — comparing recordings with the following artists: Wilhelm Backhaus (1961), Paul Badura-Skoda (1969), Daniel Barenboim (1984), Ronald Brautigam (2005), Emil Gilels (1982), Friedrich Gulda (1967), Artur Schnabel (1935)
Comparing recordings with the following artists: Géza Anda, Camerata Academica (1962) / Vladimir Ashkenazy, Philharmonia Orchestra (1978) / Daniel Barenboim, English Chamber Orchestra (1971), Kristian Bezuidenhout, Petra Müllejans, Freiburger Barockorchester (2012)