Tits do it for me. Don't believe me? Check out my profile...lol. With tits, you can hold, squeeze & play with when a girl is on top. If they are big tits they look fucking awesome jumping up & down, left to right depending on how you're fucking your gal. Such an awesome sight to see big tits jumping around.
Ass all day,real of course. Ass feels so much better in your hands and on your balls and lower abs. Tits are cool but size is irrelevant because what you focus on is stimulating the nipple.
Always trust people who like big butts because they can not lie.