All just my personal opinion
Beethoven: String Quartet op.95 — comparing recordings with the following ensembles: Amadeus Quartet (1960), Artemis Quartet (2005), Busch Quartet (1932), Chiaroscuro Quartet (2012), Emerson String Quartet (1997), Endellion String Quartet (2008), Guarneri String Quartet (1968), Melos Quartett (1984), Quartetto Italiano (1971), Takács Quartet (2004)
Beethoven, String Quartet op.18/6 — comparing recordings with the following ensembles: Amadeus Quartet (1961), Artemis Quartet (2009), Emerson String Quartet (1996), Endellion String Quartet (1996), Guarneri String Quartet (2007), Melos Quartett (1983), Quartetto Italiano (1975), Quatuor Mosaïques (1994)
Beethoven, String Quartet op.18/5 — comparing recordings with the following ensembles: Amadeus Quartet (1961), Artemis Quartet (2011), Emerson String Quartet (1996), Endellion String Quartet (2007), Guarneri String Quartet (1995), Hagen Quartett (2012), Melos Quartett (1983), Quartetto Italiano (1973), Quatuor Mosaïques (1994)
Beethoven: String Quartet op.18/4 — comparing recordings with the following ensembles: Amadeus Quartet (1961), Artemis Quartet (2008), Emerson String Quartet (1996), Endellion String Quartet (2006), Guarneri String Quartet (1995), Hagen Quartett (1999), Melos Quartett (1983), Quartetto Italiano (1975), Quatuor Mosaïques (2004)
Beethoven: String Quartet op.18/3 — comparing recordings with the following ensembles: Amadeus Quartet (1961), Artemis Quartet (2010), Emerson String Quartet (1996), Endellion String Quartet (2005), Guarneri String Quartet (1995), Hagen Quartett (2012), Melos Quartett (1983), Quartetto Italiano (1972), Quatuor Mosaïques (2005)
Beethoven: String Quartet op.18/2 — comparing recordings with the following ensembles: Amadeus Quartet (1961), Artemis Quartet (2002), Emerson String Quartet (1996), Endellion String Quartet (2008), Guarneri String Quartet (1995), Melos Quartett (1983), Quartetto Italiano (1975), Quatuor Mosaïques (2005)