How does Coke have the better product? Maybe Coke's dominance is due to choosing the right logo and sticking with it instead of constantly changing their visual identity.
That was what led to the New Coke disaster. In taste tests, five out of seven people tested preferred the New Coke taste, because it was sweeter. But when rolled out, people found it got old fast. And while now New Coke is seen as a branding disaster, the truth is if it had been a more appealing product, the brand would have caught on and it might have led to a rout of Pepsi. While most of a brand is perception, the product does matter somewhat.
Of course, I'm sure you'll find people fiercely arguing either of the products that have been competing for ages now, so trying to come up with a rubric based on your taste preference is pretty useless.
The only people still arguing are those who have not experienced the cola-nirvana that is RC cola. Interestingly enough even RC had it's own can label redesign recently, getting rid of its classy old-school look for a more modern one. The armchair designer in me preferred the old one, it seemed to fit the brand name better.
I remember back when it first hit me how perfect the logo design for the Nike swoosh was, it blew my mind. Ever since then I've tried to pay more attention to what companies are trying to portray through the images, fonts, and colors they use in their advertising and logo's.
See my reply to briansmith.