Have you done a blind taste test?
Pepsi is noticeably sweeter and has less carbonation.
I know it sounds silly to complain about soda being too sweet, but that's my knock against Pepsi. My favorite cola of all time is the Coke knockoff they sell in Cuba, which tastes like it has about half the sugar of the real thing--presumably because it is so scarce there. Real cane sugar too.
Che once threatened managers of the Coca-Cola plant in Cuba, because its drinks tasted lousy after the plant was nationalized and its operators fled with the secret formula for the Real Thing.
The story goes that he was challenged about drinking Coke while sitting on a stack of several cases. Wasn’t the company a "capitalist octopus"?
"Yes," he supposedly replied. "But in a hot climate, the people must have their Coca-Cola.
Though actually here in the UK coke/pepsi seem to have different markets - Coke rules the shop shelves whilst Pepsi seems to be the pub/cafe soft drink choice (i.e. the ones in the pumps etc. it's all Pepsi here in the UK)