Right away let me say that there are a couple versions of the Complete String Quartets by the Alban Berg String Quartett, one of which (apparently the better) is no longer being produced:
The Complete String Quartets (1999, EMI Classics)
These late '70s/early 80s recorded versions are the ones to get and/or listen to where available.
Spotify edition
According to Jed Distler on
classictoday.com this version lacks the "occasional finicky phrasal adjustment or looser-limbed ambiance marking the ensemble’s live 1989 remake". Indeed, the playing is tighter, more focused and even a bit brighter than their later versions. And the 7 disc box sets,
few of which are left, are dirt cheap compared to some of the other prestigious complete sets out there.
Compared to the Danish Quartet's recording above the Berg Quartett's version has far more verve and less heaviness. Closer, as I recall, to what Juillard (in their early formation) was doing with Op. 131. I like the Berg.