Diamond Naturals Extreme Athlete, Kirklands or Taste of the Wild?

Is one really any better then the other. I have 4 pit bulls and 2 boxers that are therapy dogs and one is my weight pull dog. They has excessive energy and I want to feed them something quality. Kirklands seems to be the least expensive at $24/40lb bag, Naturals is $35/40lb bag followed by Taste of the Wild at $42/30lb bag. There made by the same company is one really ALL that much better than the other? The breeder that gave me my last 2 dogs feds Kirklands and the dogs look just as great as mine that are on the TOTW. If I saved myself some money and went with a less expensive food would I really be comprising all that much?