When I was a kid I downed Pepsi with wild abandon. As an adult I switched to Coke because it is far superior. Diet Coke, however, tastes like a mix of piss and paint thinner. Nowadays I don’t drink regular sodas at all, so it’s either Diet Pepsi or (preferably) Coke Zero Sugar, which to me is nearly indistinguishable from regular Coke.
Vess! The Billion Bubble Beverage!
I’ve pretty much sworn off soda of any kind, but on the rare occasion I have one, it’s a Coke. Maybe a Sprite. I agree that Pepsi somehow tastes more artificial than the other leading beverage made of artificial colors and flavors. I’m sure my preference is entirely a product of advertising and the habits of those around me when I was growing up.
Most Americans, by a significant margin, prefer Coke by name. Most Americans, by a significant margin, prefer Pepsi by flavor. Back in the 80s, Coke learned the wrong lessons from this fact, and changed the flavor of Coke to be more like what people strongly preferred. It did not go well for them.
Personally, I prefer Pepsi over Coke, but RC over both of them. And I’m fortunate in that RC is also cheaper. But I’m not particular, and will take whichever is available when I’m in the mood for caffeinated sugar water.
I remember reading somewhere that when Coke tried Pepsi’s taste test but offered more than a swallow, the preference swung back to Coke. Pepsi’s sweetness was fine momentarily, but for extended drinking, Coke was more palatable.
Coke. Pepsi is way too sweet.
And the diet version of either tastes awful.
And yes, I can tell the difference in a blind test.
Coke Classic, the Real Thing. 
I love Cherry, Lime, and Vanilla Coke, too.
Coke by a mile.
I rarely drink soda anymore. When I was young my drink of choice was Bacardi and Coke but these days I find it far too sweet. In the past when I ordered Coke in a restaurant and they offered Pepsi I declined. I remember when Coke created New Coke. One of my friends and I did a blind test and both preferred the Coke Classic. I detest diet anything. Too fake.
That’s the main reason I prefer regular Coke over Pepsi. Pepsi tastes sweeter, or something, to me. The other is Coke is spicier, and Pepsi is more citrussy. When I was a kid and took the “Pepsi challenge,” I literally always picked out Coke. (Of course, now that I’m a diet drinker, perhaps I shouldn’t be talking about which tastes better. 
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I don’t hate Pepsi, but I definitely don’t like it.
I very rarely drink soda, but when I do, it’s a coke-a-cola. I actively avoid restaurants that serve Pepsi. Can’t stand the stuff. Pepsi is like drinking syrup, and leaves me thirstier than I started. Coke is my ultimate restorative, with the perfect blend of water, caffeine, and sugar to revive me when I’m tired.
If I should accidentally find myself in a restaurant that doesn’t serve coke, I’ll have an unsweetened iced tea, or plain water.
Ugh… I prefer Pepsi, if I have to drink one of these two colas. Diet Coke, however, over Diet Pepsi. Diet Pepsi tastes salty to me.
I see I wasn’t the only one.
Coke.
Sorry, we don’t have Coke.
Then anything is fine, including Faygo, Pepsi, generic cola.
Definitely Pepsi. I can tell the difference.
The essence of “cola” flavoring is a mixture of vanilla, cinnamon (or cassia) and citrus and other oil (not juice). as William Poundstone points out in his first Big Secrets book, this basic formula is pretty well-known, and is in reference books like Merory’s (which is why all colas taste approximately the same – which is nothing at all like the flavor of Kola nut extract). Cunningham’s For God, Country, and Coca Cola corroborates the formula. The difference is in the composition of that third ingredient, which is supposed to be a mix of oils from plant rinds – orange, lemon, lime, for all I know grapefruit and tangerine and neroli, with the possibility of things like lavender oil tossed in. If you have your own gas chromatograph/mass spectrometer you could probably figure out the exact compositions of Coke, Pepsi, and store-brand colas. as Poundstone notes, speculation is that Coke is heavier on orange and Pepsi heavier on lemon, which is why Pepsi once marketed a version with lemon in it. It could be – I don’t know, but it’d explain the difference, yet why they’re so close.
Pepsi always tastes like cleaning solution to me.
Pepsi. I prefer the sweetness over Coke’s bitterness. Not to say I don’t like Coke, I do. But I like Pepsi better.
I haven’t had either in years, but I prefer Pepsi from a can and Coke from a fountain. But even better is 50/50 Coke/Sprite!
I voted for Pepsi/Diet Pepsi, but I really hate all diet soda, so would choose Pepsi/Coke if that was an option. (Really prefer Cherry Coke or best of all Dr Pepper, but we’re not supposed to say so in this poll!)
Pepsi is fizzier, which makes it better to me. Coke reminds me of when I was sick to my stomach as a child, and my mom would give me Coke syrup because it would stay down when all other foods–and even water-- would make me throw up. Therefore to this day, Coke tastes like medicine to me.
That could be. My general impression is that Pepsi is just more citrussy overall (and it may be specifically lemon I’m getting there) and Coke is a little heavier on the spices (like vanilla or cinnamon or something in that ballpark.) I suppose orange vs lemon can also explain some of that impression, as oranges are a bit more varied and “spicier” to me in flavor than lemons, which to me is my default “citrus” flavor.