Nicholson
Well, they are better actors and have stronger careers. I love him though, this was not meant as criticism.
De Niro and Nicholson have been doing the same shtick (playing themselves) for a very long time.
If anyone plays themselves its Keitel, he looks and sounds the same in practically everything he does. De Niro and Nicholson are way more compelling to watch.
Nicholson barely did any movies after 1997!
And still he does the same shtick.