I keep seeing this comparison in both forms for both Superman and Batman. The truth is that it depends on the story they're in and the author's leaning. Sometimes the author wants to tell a story about Superman's moral center, which comes from Clark. Sometimes the author wants to tell a story about the difficulties of pretending to be human when you're a god. Both characters can go either way.
It's a sign of a good comic book character when you can tell different -- even conflicting -- stories about them, and when every fan has their own preferred slant on the character.