Ass
Not even a competition. As stated previously, a quality ass is usually the result of hard work on a girl's part. Nice ass = nice legs & tight core = banging ass body.
Tits are just fat bags. Don't get wrong, I love me some nice fat bags, but anything over a c-cup is just problems in the future. While they might look great at the prime age of 20, its all downhill from there. No one likes saggy tits and stretched nips.