The story of Richard Donner, the Salkinds and Richard Lester is one that can be found on Wikipedia, and so I don't need to repeat it. This is a review of both the Richard Donner Cut, and the HD DVD capabilities. First off, the film is much darker and resemblant of the original (by Richard Donner). The original Superman II was completed by Richard Lester (who went on to direct the much less successful, Superman III), and there isan obvious contrast between the Donner-Lester scenes. Under Richard Donner, all of Gene Hackman's and (most of) Margot Kidder's were filmed, and such they did not work with Lester, and so it can be said that all Richard Lester did was remove alot of Donner's work and re-film them, and so in the original Superman II there were alot of continuity errors between the two. The Richard Donner Cut irons out the continuity, and tells the original, untouched version of Donner's original vision.
While the HD DVD is dead, there is no denying that it does offer crisper vision and great extras, and Superman II: The Richard Donner Cut is no different, save for the fact that the film was made in 1978 and 1979, so the effects obviously aren't stellar, but they were for the time. The commentary has Richard Donner and co. discussing certain techniques, aswell as topics such as Richard Lester, Alexander and Ilya Salkind, Christopher Reeve, the budget, effects etc.
En memorium to the late Christopher Reeve: "Without whom we would never have believed a man could fly", The Richard Donner Cut will provoke any Superman fan's true feelings toward the great film series (or at least, Superman I and II).