found another article. it's kinda old but it does categorizes dog foods by brands and lines, according to "performance", "super premium", "premium", "regular", and "economy" type foods.
http://www.gooddogmagazine.com/drydogfood.htm
it appears that you should not only look at ingredients and how it's produced (without or with little preservatives and coloring) but also % of protein, % of fat, % fiber. even within the same brand of dog food, the same manufacturer will have a "performance", "super premium", and "premium" lines, depending on your dog's needs.