This is all your fault, ladies. If you had BOTH then there wouldn't be either/or.
Naaaaah just kidding, I only care for a big brain anyways.
But it's not just the ass that makes the ass a good looking ass. A good looking ass is complemented by long legs, great thighs, calves and especially wide hips, that's what makes the ass a good looking ass. Ass, ass, ass! Therefore ass beats tits in most cases because tits are not complemented by any other body parts. They are lonely.