There are of course many fine SQ recordings by fine ensembles. Some of my faves are:
LvB – Vegh (stereo), Budapest (mono, United Artists), Prazak (Praga)
Bartok – Vegh (stereo), Emerson
Shostakovich – Danel, Borodin (Melodiya), Emerson
Haydn – Tatrai (Op 76), Budapest (Op 76), Mosaiques (all they’ve recorded)
Schulhoff – Petersen
Schubert – Takacs (14), Panocha (15)
Dvorak – Panocha (10-14), Pavel Haas Quartet (12)
Martinu – Panocha
Janacek – Prazak, Panocha, Talich (1989 recording), Pavel Haas Quartet
Prokofiev – Pavel Haas Quartet
Debussy/Ravel/Faure – Ebene Quartet
Villa-Lobos – Cuartetto Latinoamericano