As far as colas go I have drank both Pepsi and Coke and to me there is no comparison.
We each have our own opinion on this but I prefer Pepsi because it has a less sweet taste and I do not like an overly sweet drink.It is also very thirst quenching and I drink it now and then.
I have to have the regular. I do not care for diet sodas of any kind as I do not like the after taste.
If I were not feeling well I would go for the more sugary one as that would settle my stomach more but just to drink I will take PEPSI any day over COKE.