What a fun topic. I LOVE Pepsi. I find this delightful kaala pani quite comforting. I watched the history of Coke/Pepsi on the Food Network channel. In a blind taste test, most people prefer the taste of pepsi. In the beginning of their history, Coke was in the lead because it used talented artists to illustrate its advertisements and since Coke was more expensive than Pepsi, it was considered a luxury drink and that made it popular for quite some time. Until Pepsi fought back with the blind taste research and gained a huge following. Pepsi is also more associated with youthfulness and it has used famous young celebrities for marketing.
I like Coke as well, but prefer Pepsi more. It's sweeter:)