All just my personal opinion
Beethoven: String Quartet op.59/3 — comparing recordings with the following ensembles: Amadeus Quartet (1959), Artemis Quartet (1998), Emerson String Quartet (1997), Endellion String Quartet (2007), Guarneri String Quartet (1966), Guarneri String Quartet (1992), Kuijken Quartet (2006), Melos Quartett (1984), Quartetto Italiano (1974)
Beethoven: String Quartet op.18/1 — comparing recordings with the following ensembles: Amadeus Quartet (1961), Artemis Quartet (2010), Emerson String Quartet (1996), Endellion String Quartet (2008), Guarneri String Quartet (1995), Hagen Quartett (2003), Melos Quartett (1983), Quartetto Italiano (1972), Quatuor Mosaïques (2004)
Beethoven, “Eroica”-Variations op.35, Comparing recordings with the following artists: Artur Schnabel (1938), Glenn Gould (1970), Svjatoslav Richter (1970), Emil Gilels (1980), Konstantin Scherbakov (1984), Alfred Brendel (1985), Olli Mustonen (1993), Ronald Brautigam (2010)
Beethoven: 6 Bagatelles, op.126 — Ashkenazy (1984), Brautigam (2010), Brendel (1964 & 1985), Gould (1974), Schnabel (1937); Beethoven: 24 Variations on the Arietta “Venni Amore” by Vincenzo Righini, WoO 65 — Pletnev (1997), Brautigam (2012); Schubert: Symphony in B minor, D.759 (“Unfinished”) / Symphony in C major, D.944 (“Great C major”) — Furtwängler (1952), Harnoncourt (1992), Dausgaard (2006)
(…) Sometimes, such videos are excerpts from interviews and other collaterals (…). The first experience that I want to talk about here is about a recording of the Beethoven piano concertos with unnamed artists (…). I had certainly heard about all the artists, but I did not have any recordings with that pianist at all so far…