Saw Josef von Baky's Munchhausen, with Hans Alber in the title role--he's much more charismatic than John Neville (looks a bit like a German George C. Scott), and the special effects were wonderful. Baky's version doesn't have a supporting performance from Robin Williams, and I'm guessing Gilliam has the advantage (somewhat) in terms of production budget and special effects (some of them--the sea turning into moondust--is quite lovely), but Baky's version has a more moving conclusion, something I felt Gilliam's lacked.
Many of the episodes are similar--I can see where Gilliam got much of his inspiration, or even shots--but the episode with the Sultan's bet over a bottle of wine seems odd. It's on both film versions, but I don't find it in the original book. It is, however, found in one of the Brothers Grimm fairy tales (written later than Munchausen's book), about a band of super-powered brothers.