Depends on the girl, some girls are greatly buffed with the small addition of a good booty, some have a face that enhances a good pair of juggs making it a solid combo. Some need both to be worth the look. Some can't be saved no matter how OP both the titties and booty they have.
Personally though the first thing I look at is the booty, if she ain't got one I don't even scan the face, my mind just skips it <___>
Titties are nice and all don't get me wrong, but booty is way too OP so it's not a fair fight.