If anyone deserves to be in Purgatory - the weirdest metaphysical concept of them all - it's Franz Anton Hoffmeister. True, he commissioned the two Piano Quartets in question and the eponymous String Quartet in D Major (K 499) - whoelse can say as much - but on the other side of the ledger, he cancelled the original contract (for three Piano Quartets) he had with Mozart on the basis that the G Minor was too complex for his audience. Thankfully, Mozart wrote K 493 in any event, leaving the last Piano Quartet as a project in limbo. Hans Keller, the great Austrian musicologist, asserted that K 478 is conclusive proof that Mozart is the only person in history to have had an infallible ear. Indeed, Mozart practically invented if not perfected the Piano Quartet. Beethoven and Mendelssohn composed some duds in the genre. Schumann's Opus 47 and Brahms' Opus 25 & 26 are all fine works (to my ears, the latter's Opus 60 is boring, much like the Piano Trios Opus 87 & 101).
In terms of K 478 & K 493, I am conversant with the following performances: the Beax Arts Trio; Ingrid Haebler with members of the Berlin Philharmonic; Walter Klein with the Amadeus Quartet (on vinyl - amazingly, it has yet to be released by DG onto CD); Richard Burnett with the Salomon Quartet (on Amon Ra in a Festival of Caterwauling) and Mal Bilson's performances on DG Archiv (the Pale Rider cometh).
I was floored by this newcomer. It left me punch-drunk and flummoxed. It's now my primary recommendation in this field. It's gutsy, refined and stupendously recorded (at any given point, one can follow the trajectory of the viola with precision). The Ysaÿe Quartet and pianist Jean-Claude Pennetier were but names to me but no longer. The latter in particular is a natural Mozartian - what touch he has! The string tone of the three members of the YQ is "full fat" - it's far removed from the anaemic feline imprecations of the Salomon Quartet. From the first note to the last, the music-making is touched by distinction. For the duration of this disc, one thinks: there is no other way to play this music. It is an act of utter consummation with no ash to its name. With its finale being in G Major, K 478 charts `per aspera ad astra' (through struggles to the stars): it is resplendently realised here. The development section of K 478 / 1 is Mozart as Prospero: I have never heard it played with such mystery, venom and mastery. The newbies adopt a more pacific approach to the first movement of K 493 than the Beaux Arts Trio: it so works! All repeats are observed; for once, I welcome the practice. One luxuriates in the plenitude of Mozart's genius.
Leave Hoffmeister in Purgatory. Purchase this disc; be blessed in Paradise.