The only "sure thing" is that Beethoven sonata interpretation (or that of any other music) whittles down to personal taste, which will vary from person to person. I know this sounds like "very obvious talk" but in the world of music critique, classical music critique specifically, there seems to be an unspoken (occasionally spoken) rule that you need a music science degree and/or fifty recordings of "sonata X" to truly know what is good, what is bad. That of course is simple hogwash.
To some, the perfect/ultimate collection consists of one artist's interpretation; to others, it's a hodge-podge.
Many people like Schnabel because he was such an early visionary in terms of his (some say overly) academic research on the sonatas (some of his footnotes ARE unintentionally hilarious), but as the times change so do his recordings. Some might call them quaint today (I would not go so far; I like Schnabel, and I believe it's the poor quality of his recordings that most people seem to find "quaint").
Rubato-laden interpretations that would be dismissed with a casual wave today were all the vogue over a hundred years ago, and the reverse would also be true... the mid-century drying-out of tone and metrical lines would be unthinkable in Lizst's time.
There's this constant striving for a middle ground with tempo, especially in the later sonatas like the
hammerklavier. That one in particular is so large in thematic scope, like a symphony, that you find people really experiment with speed, as they have with large symphonic works by later-century composers.
I find most recordings try things that I appreciate (especially recording staccato and tempo) but they're not always to my taste. I, like everyone else, have an "ideal recording" in my head against which
every recording I hear has to "compete".
The abovementioned interpreters are great starts. The Richard Goode set, which I acquired for a measly $30 about six years ago, is a nice starter set. I find it very "even"; in other words, Goode is very consistent and somewhat conservative in his vision through all of the 32, so you can more easily make up your mind about which ones you like (and don't), and HOW you want them played (and don't).
It's mostly about emotional resonance (furthermore: life context, or "what you were doing when you first heard it") ... my favorite recording of the
appassionata is still a cheesy budget RCA recording from the eighties by Claude Frank that I listened endlessly in high school (missed notes and all!).
As with other things we could mention, it's often "all about the first".
~s
