For me, I can read anything Tosches writes about. I enjoy his writing first and usually the subject second. I'm not sure how close or unreliable it is. In Dino, for example, this is really a story about how little we can ever really know someone. In the end, Tosches portrait of Dino tells us so much more about the environment that produced Dino than any other Dino bio.
Fiction sometimes uncovers the truth more appropriately than non-fiction.