I think this is the best live recording of Götterdämmerung available. The stereo sound is really surprising in its quality. This gives it an immediate advantage over the mono Knappertsbusch cycles of the same era, which, whilst very good performances, would certainly benefit from better sound quality. On the other hand, I don't think this recording would.
Unlike Knappertsbusch, Keilberth does not periodically go to sleep on his orchestra: The drama and tension are built up, sustained, and released with perfect timing. The conductor keeps the work on its trajectory unfailingly and with pinpoint accuracy.
There's also a lot of passion, the lack of which is perhaps the main criticism levelled against studio recordings. There is not here the perfectionist attitude which can sometimes sterilise a performance: take for instance Siegfried's journey to the Rhine at the end of the Prologue. The orchestra sounds really as though it's straining at the limits of its ability, but the effect is not to bring into question the competence of the players, but to show that the level of emotion simply cannot be contained.
The singers are, as you would expect from some of the greatest Wagnerian names, pretty good. I think this is the best Varnay I have heard, there is none of the melodrama to which she was occasionally prone, and not a hint of a screech. Windgassen is genuinely youthful, Greindl blackness personified, and there has never been anyone to match Neidlinger as Alberich.
The most remarkable thing, however, is that it took fifty years before the public were allowed finally to appreciate this magisterial achievement.