Gould was a brilliant exponent of Bach's music played on the piano - he revolutionized the concept at a time when it was considered by many to be "inappropriate" to play it on anything other than the original instrument.
His music however is highly idiomatic and served up in a manner that serves the performer rather than the composer. His recordings of composers other than Bach are less critically well received and he was an outspoken critic of romantic composers in general, even to the point where he was less than complimentary about the works of Beethoven and Mozart. He did play some of the later sonatas of Beethoven and also some works by modern composers such as Schoenberg, but it is Bach that he is rightly famous for.
He was famously eccentric, but how much of his odd behavior was for effect - who knows?
His playing in general was rife with idiosyncracies, odd tempos and strange phrasing. If you are looking for versions of works that are attempts to interpret the composer, then I suggest you look elsewhere. If you are looking for baroque period works that have been processed by a remarkable mind - then Gould is your man. Personally I prefer my Bach (and most other classical music for that matter) less 'mannered.'
Glenn Gould