When I purchase ketchup, the first thing I look at are the ingredients. I make sure corn syrup or high fructose corn syrup are not listed. Then I go look at the price of the organic version. If there isn't much of a difference, then I'll buy the organic. For some reason I find organic ketchup infinitely better than its nonorganic counterpart.
With big name brands, this basically excludes Heinz and Hunt's, who both list the above mentioned ingedients in their ketchup. So I believe that leaves Del Monte and a number of other smaller companies who skip the syrup.
Erik