Some of his music reviews were pretty good: Arnold Dolmetsch really was a revelation, and surviving recordings suggest that Joseph Joachim playing Bach really was like an attempt to scrape a nutmeg on a boot sole.
But Shaw strikes me a lot like Twitter. He spoke and wrote less because he had something to say than because he wanted people to hear how well he said things, and his reach increased because people enjoyed how well-put his remarks were and how stylishly he put down objections, rather than because of the quality of his opinions.