Regular Pepsi is much better tasting IMHO than Regular Coke. I think they use an HFCS with a Higher Fructose content than Coke, because its stronger tasting and sweeter, yet has the same amount of HFCS. I read somewhere where a Diabetic had said that Coke raised her Blood Sugar faster than Pepsi, which if Pepsi is higher in Fructose, and thusly lower in Glucose...would make sense. As for Diet Coke vs. Diet Pepsi, I really can't tell the difference. They both taste Chemicalish to me, though I can get used to that with time. I definitely prefer Diet Rite on taste. I haven't - and don't plan to ever, unless they drop the HFCS - tried the Coca Cola C2 or Pepsi Edge, so I can't say how they taste. But, I would guess the Pepsi would be better because its made with Splenda [which actually does taste like real sugar,] instead of a Cocktail of Artificial Sweeteners [including Aspartame] as Coca Cola used.