I'm watching the original Cape Fear (1962, B&W), with Robert Mitchum and Gregory Peck...a great classic, with Mitchum playing a part he was born to play. Gregory Peck, as always, was good, and it has some good character actors, as well. I like B&W movies, and usually prefer the old style suspense movies to the newer, more graphic ones. I'm a great fan of Robert Mitchum, simply because of his attitude and approach to acting (just a job - he never even watched the finished movies).
But I can't honestly say Mitchum was better, because DeNiro was just so good, especially when you consider that he's a New Yorker playing a southern redneck.