I was watching Al Pacino being interviewed on The Actor's Studio this afternoon. I recall the first time I saw Pacino. It was in The Godfather. I thought, "Why did they get this guy to play Michael? He looks like Dustin Hoffman, but he's not as good."
Now that I have watched them in numerous films roles, it is pretty clear to me they are different. Hoffman has much broader range than Pacino, and yet I cannot imagine Hoffman in Scent of a Woman, and I cannot imagine how The Godfather series would have played out with Hoffman instead of Pacino.
My understanding is that Hoffman is brilliant, works extremely hard, and that Pacino is... well... different.
No matter. I have enjoyed them both in their various roles.