Amadeus is an almost perfect realization of its central conceit. If you accept that conceit (and I find it tremendously entertaining to do so, for the sake of the argument) Forman's picture plays it out flawlessly, assisted by phenomenal acting: Abraham's great brooding self-hating Salieri, Tom Hulce's hilarious embodiment of Mozart as a sort of 18th century version of Jerry Lee Lewis, not to mention Jeffrey Jones' brilliant portrayal of Emperor Joseph as a stolid, well-meaning bureaucrat trying ever so hard to be a good and creative philosopher king in defiance of his true (dull) nature. The music is performed and explained in a way that non-classicists can follow and learn from. A moving delight that rewards repeat viewing.
