prism is a decent food, and if you compare it to others in its class and quality level, it's probably the best.
i do not agree with adrienne that corn is a "bad" ingredient per se, it's as good of a source of carbs like other grains and unless an individual dog has an allergy or sensitivity particularly to corn there is
no reason to avoid it. of course you wouldn't feed any food containing a particular ingredient if a dog is allergic or sensitive to it, but that doesn't only go for corn, wheat or soy, but also for
any other component. i know of a beautiful yellow lab for example who is highly allergic to rice and does miserable on any food that contains any form of rice.
you can compare the nutritional value of yellow corn and brown rice
here for example. as you see, the difference is rather subtle.
in a nutshell, the claim "top allergen" means nothing unless your dog is affected by it. look at how many dogs eat flint river ranch foods for example and do well on them - and their main line of products contains whole wheat as a main carb source.
even dr. pitcairn includes corn and wheat in his recommendations for home prepared diets. one big difference is that the corn in all the poor quality, bottom-of-the-barrel foods is basically garbage quality, often contaminated with rodent droppings, mold and other substances that make shipments unacceptable for human consumption. once they are rejected for use in human food production, they are used for animal feed.
eagle buys all their corn from growers who grow it exclusively for eagle, it is non-GMO and grown without the use of pesticides.
i wouldn't feed the prism "maintenance", since it doesn't have meat as a first ingredient and has "poultry liver digest", but the othe varieties are better formulated.
the lamb formulas is overall ok, but it is not a
true lamb based food. it contains chicken fat, and any dog who is allergic/sensitive to chicken products of any sort will still have issues eating this food.
last but not least, i like that eagle doesn't use menadione, even in their budget line.