I take both sometimes. But they are harmful for health. It is better to take butter milk, fruit juices- fresh or coconut water or milk. It is best for health.
in between these I prefer Pepsi otherwise my favorite is thumbs up its really stronger than both of them.
I think in general Pepsi tastes better, but when you just drink Coca-cola you ll want to change sometimes to Pepsi and vice-versa.