It all depends to be honest.
If we're talking about the regular versions, then Pepsi is by-far the better tasting brand. If you haven't done it yet, drink a can of Pepsi, and then drink Coke afterwards, and you'll understand what I mean.
Pepsi, overall, is sweeter, and more appealing to the tastebuds. Coke is much more bitter than Pepsi is, and isn't much appealing to the tastebuds. However, their flavor variants are contenders with each other.
Example: If I had to choose between Vanilla Coke over regular Pepsi, I'd choose the Vanilla Coke, because the vanilla actually adds to the flavor, and gives it that extra Sweet flavor that the original version is lacking.
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