I think it's more informative to judge a brand by the profitability of the company owning it. I like to use return on equity:

                   | Coca-Cola Co. | PepsiCo
  return on equity | 27.51%        | 34.83%

I was expecting Coke (KO) to be way ahead, but actually Pepsi is trouncing them - over the last 12 months, according to Wolfram).

http://www.wolframalpha.com/input/?i=KO+PEP (you need to change the drop-down menu from "Fundamentals" to "ratios" - wolfram doesn't seem to have a way to get a link with a particular menu selection).

OK, so here's data that better fits my preconceptions, looking at the rat e of growth of equity, over the last 3 years:

         2005          2008 
  Coke:  29,427.00 --> 40,519.00 = 37.7% over 3 years
  Pepsi: 31,727.00 --> 35,994.00 = 13.4% over 3 years

http://www.google.com/finance?q=NYSE:KO&fstype=ii (balance sheet, annual data)

http://www.google.com/finance?q=NYSE:PEP&fstype=ii (balance sheet, annual data)