Pacino is so much better as an actor than De Niro it's not even funny, the latter is so monotone in his performances and is often the weakest part of the movies he's in (e.g. Goodfellas where basically everyone else gives an incredible performance with Joe Pesci being a standout) at least past the 1980, meanwhile Pacino has some absolute bangers under his belt and an actual range, even if people clown on him for getting the Dunkaccino bag
Drop everything and watch Dog Day Afternoon blind tonight, directed by one of the best to ever do it Sidney Lumet, starring Al Pacino with the best performance of his career and incredible John Cazale among others