"Affection" is the wrong word. The Fuge,performed as the conclusion of the entire 130 quartet is a beautiful piece of music. Occasionally terrifying, but nonetheless beautiful, haunting and unforgettable if performed live.
Note that Gutmann's "affection" quote comes from a critic who died a 120 years ago. It's perfectly alright to say that the GF did not get a lot of affection of conservative Victorian critics, but essentially that's completely irrelevant to how we feel about this piece today.