We happened to have all 3 bottles in our fridge so we did a taste comparison tonight. As previously discussed, Canadian and Organic versions don't use High Fructose corn syrup.
Canadian Heinz- bright and sweet taste- this is the ketchup I remember from all those McDonalds packets of my youth.
Heinz Organic- more complex, almost a molasses flavor, color is a darker red.
Normal Heinz- tasted blah and fake in comparison to the others.
Canadian Heinz and Organic Heinz are pretty similar in ingredients. Both list Tomato paste (or concentrate) first. Canadian's next ingredient is sugar- Organic's next ingredient was vinegar, which makes sense given the difference in taste. Other ingredients were pretty much the same (except organic vs. non-organic ingredients, such as onion powder). However, Organic lists, as its last ingredient "Natural Falvorings".
So if you are a Heinz ketchup purist, get the Canadian version. The only problem is you'll never be able to buy the US version again. If you like the Heinz flavor but don't want it too sweet and like a bit more interesting flavor, get the Organic. And then throw away your "normal" Heinz.
We bought the Canadion version at http://www.canadianfavourites.com/