Sugar vs high fructose corn syrup. It's probably not worth getting into an in-depth discussion about this, only to say that a shift occurred in the mid-80's with the glut of corn (see book review) when the major soft drink manufacturers changed their formulas. "New Coke" was forced on us, and it was sweetened with HFCS. It tasted different, we all seemed to hate it, and Pepsi tried to tell us that they had won the taste test. The public doesn't like change, and the market forced a different product. Enter Coca cola "classic," which wasn't classic. It was a contrived formula of flavors that tasted more like the original non-HFCS than "New Coke."
So what, right? That's how it's been since around 1985 or so, and if you're younger than 30, you probably couldn't care. But for those of us with a couple more miles on us, we always knew that coke classic didn't taste quite right, but we got used to it. Enter the time capsule known as the Mexican grocery store. In Mexico, sugar is still used as the sweetener instead of HFCS.
Check the label, and you'll notice that instead of HFCS, the sweetener used in this drink is sugar. The taste is different, and it's a throwback to what many of us may remember as the original flavor of Coke, back when every type of soft drink was referred to as a "Coke," even if it was something else like sprite or pibb. It may explain why Pepsi won the taste tests, since it came across as sweeter, more like the original coke flavor without the weird aftertaste we've all gotten used to.
Coke classic? Yeah right. How about "new New Coke." Fortunately for the company, it was just enough like the original that it stuck. I can't tell you which one is better, that's obviously personal. But if you remember Coke as a kid in the 70's, and want to relive a little bit of childhood, go to the Mexican grocery store, and read the label. Unless you live in a big enough Jewish community that offered Kosher Coke with a yellow cap for Passover. They changed it for that, too.