I'll complete the spectrum of opinions by stating that the third segment (Fellini's) is by far the best, with great cinematography, and feels like La Dolce Vita mixed with Mario Bava.

By contrast, Vadim's "Metzengerstein" is superficial and boring: it looks good but the story is a mess and is stretched out to breaking point, and Malle's "William Wilson" captures some of the atmosphere of Poe and is entertaining but ends unsatisfyingly and doesn't really have much interesting about it.

Alain Delon gives a fine performance in the second film, Terrance Stamp is terrific in the last one. Jane Fonda is astonishingly beautiful but is mostly there to be decorative, though it is a little daring to have her real life brother be her romantic fixation. I don't think they'd have cast this like that in the U.S.

I really liked the 1st part. I loove the 60s aesthetics in it.