Tip, if you feel I am being to pushy or anything, let me know and I'll stop
Iams' ingredients:
Chicken,
Chicken By-Product Meal,
Corn Grits,
Corn Meal, Chicken Fat (preserved with Mixed Tocopherols, a source of Vitamin E, and Citric Acid), Fish Meal (source of fish oil), Dried Beet Pulp (sugar removed), Dried Egg Product, Natural Chicken Flavor, Potassium Chloride, Calcium Carbonate, DL-Methionine, Brewers Dried Yeast, Choline Chloride, Vitamins (Vitamin E Supplement, Niacin, Ascorbic Acid, Vitamin A Acetate, Calcium Pantothenate, Biotin, Thiamine Mononitrate (source of vitamin B1), Pyridoxine Hydrochloride (source of vitamin B6), Vitamin B12 Supplement, Riboflavin Supplement (source of vitamin B2), Inositol, Vitamin D3 Supplement, Folic Acid), Salt, Minerals (Zinc Oxide, Manganese Sulfate, Copper Sulfate, Potassium Iodide, Cobalt Carbonate), Rosemary Extract
The ingredients I bolded are poor quality (but there are many more). Cats are pure carnivores and can't digest corn very well, but corn is still one of the main protein sources in the food. Corn is also a major allergin in many cats and dogs. By-products, although not inherently bad, very greatly in quality... one batch might have organs (good) while another is nothing by beaks and feet (not so good). It is a very inconcistent source or protein, and sometimes not very digestable.
Chicken Soup Ingredients:
Chicken, Salmon, chicken meal, whole grain brown rice, chicken fat (preserved with mixed tocopherols), oatmeal, whole grain white rice, potatoes, cracked pearled barley, millet, turkey, duck, flaxseed, egg product, natural chicken flavor, carrots, peas, apples, dried skim milk, kelp, cranberry powder, rosemary extract, parsley flake, salt, choline chloride, dried chicory root, methionine, potassium chloride, taurine, zinc proteinate, vitamin E supplement, niacin, manganese proteinate, copper proteinate, zinc sulfate, manganese sulfate, copper sulfate, thiamine mononitrate, vitamin A supplement, biotin, potassium iodide, calcium pantothenate, riboflavin, pyridoxine hydrochloride (vitamin B6), vitamin B12 supplement, manganous oxide, sodium selenite, vitamin D supplement, folic acid.
The first 3 ingredients are much better quality (animal protein named by specie) and are not by-products, which makes the nutrients much more digestable for the cats. Also, at least in my area, I pay $12 for a bag of Iams at Wal-mart (7 or 8lb), and $8-9 for Chicken Soup from my LPS. So it's actually cheaper and higher quality food and I also get to support a local store rather than a chain.
Somethings you'll notice are a much healthier, softer, shiner coat, usually with a *ton* less sheddin. Most likely fewer health problems, including a reducted chance in obesiety, and a chance at more energy in your cat.
I don't consider myself educated enough to go into all the details, but I do stongly encourage you to read info on
http://www.mordanna.com/dogfood/ . Although it's for dog food, most of the principles hold the same for reading lables.