I have not had the chance to listen to all 36 CDs as yet, but having heard all the Bruckner Symphonies, the Beethoven Symphonies (not the Choral so far) and Tchaikovsky Pathetique, I can only say this is a magnificent set of clear recordings with dramatic and sensitive conducting. I look forward to hearing the Mahler, Brahms and Schumann offerings. The recordings cover a period of thirty years, from the early sixties to the late eighties. Many recordings are ADD but the later ones are DDD. I really cannot tell the difference in sound quality. Haitink and the RCO really have made a an outstanding contribution to recording history and the whole set for £50 is outstanding value. Haitink is clearly a master conducter who knows how to bring the best out every instrument under his direction. This is a must have set even if you own complete recordings of symphonies such as Beethoven, Brahms, Mahler etc. conducted by Karajan, Kubelik and Bernstein or Stokowski.