Pepsi specifically Pepsi Max. Not only is it great on it's own but I love it with Jack Daniels and ice, Coca Cola doesn't taste quite right with whisky.
If we're talking regular Coke and Pepsi, then I prefer Pepsi. Coke always makes me feel like I'm drinking battery acid, but I will say that it makes for a better drink mixer than Pepsi.
If we're talking the different flavored Cokes and Pepsis, then Coke tends to have better flavored variations than Pepsi in my opinion. I do love me a Vanilla Coke from time to time, while Vanilla Pepsi is quite nasty, and I'm sure it's the same for the cherry versions.
Pepsi has more spice in their recipe, Coca-Cola markedly less. I picked Pepsi because I prefer the stronger (and more traditional) Cola-spice taste, but I guess it's not for everyone.
If you find traditional Cola-makers or ask your parents/grandparents what Cola used to taste like, you'll find it was like a more spiced version of pepsi.
This curiously invigorating cola is inspired by traditional colas from yesteryear and made using infusions of the finest herbal ingredients including sweet cinnamon.