Dir: Martin Scorsese
Intentionally viewed after On the Waterfront. If Brando is a man who could have been a contender, De Niro was one and lost it through his own inner demons. Brando was a simpleton caught in a bad situation by people who should have been looking out for him. De Niro brought it on himself. Jake La Motta had everything and gave it away.
Bull is more tragic and bleak, and I think the slightly lesser story as a result. Brando's eventual redemption makes for a more complex narrative, even if the character development in Bull is superior. And of course, judged from a technical level, Scorsese wins hands down.
Dumb to compare the two, I know. But the ability of Waterfront to tell a timeless story in a fresh and compelling way fits my personal aesthetic preferences for a movie narrative just a touch better than Bull.
Still, Raging Bull, BME