Ashes is such a different kettle of fish to regular cricket, it's all about how you cope with all the tremendous external pressure. In 06/07 England were badgered into the ground by everyone in Aus, the press, the crowds it was quite intense at the time and you could tell there was nowhere to hide even for a guy who thrives on it like Fred who looked quite down and out at the time. When we go to England I think our players really lose it sometimes, the small grounds, the noise, the tabloid press, the enormity of the occasion, I think it becomes like a pressure cooker and you can tell that a) it revs up the home bowlers and b) it throws our batsmen off their game. Plans go to pot, selectors go nuts trying to find any magical combination, it's insane.
What I'm trying to say in a long winded way is that we can discuss how good each side is till the cows come home, but to a certain degree (once each side is past a certain proficiency threshold) it becomes slightly irrelevant.