North American Sodas: USA vs. Mexico vs. Canada-How Different Are They In Taste?

[bbqboy]

I'm asking this question because of a tangent in the Heinz Ketchup Canada vs. USA Catsup thread.
How different are the major brand formulas between the 3 countries?
Beyond sugar vs. HFCS, I suppose.
Are major US brands formulated regionally? Or Canada and Mexico, for that matter.
Original query-
http://chowhound.chow.com/topics/7277...