User blog comment:Fatimafaye/Who Do you Think?/@comment-1478533-20120420031906

Near the beginning of the show, it seemed the case that Phineas was a dreamer and Ferb an inventor; Phineas thinking of what to do and Ferb thinking of how to do it. Since then, Phineas has been shown to also be extemely proficient at building things, and they're more or less on equal ground. You can say Phineas is smarter since he seems to also be more creative, or you can say Ferb is smarter since he seems to have more hidden depths to him.

Their intended portrayal seems to be that of two equally brilliant minds who wouldn't do things nearly to the scope that they do without each other. They are not better at much of anything than the other is. (Though Phineas seems to be very much better at talking!)

So, my answer is "neither".