My avatars are probably a hint that I have a fondness for the female derriere. I actually love both but a terrible ass on a great set of tits is a deal breaker. Regardless of cleavage I damn near get whip lash whenever a perfect booty passes my way.
Between the two I am more of a Tits guy. But then I think a womans most compelling and attractive features are her face and eyes. Tits and Ass come later...