To be honest, I think that's asking the wrong question. The greats don't take a "defensive" or "offensive" stance per se, but rather play in a way that is well-suited for both, and attack/defend only when it is necessary.
Though to be fair, a purely defensive stance is probably too passive to win much.
We have seen the great players play. How do they play? What strategy do they use? Do they prefer defense against offense?