The reason I don't use the "adult" formula is that I am literate, and knowledgeable on digestion. I don't read the bag fronts, ever. I read the ingredients, only. Nothing else on a bag matters.
Dogs are carnivores, not as carnivorus as cats, but their teeth are not shaped like ours[we are omnivores]. Their diet is different from ours, indicated by the shape of their teeth.
With the exception of animals diagnosed with organ failure, it is a fallacy that a high protein diet harms dogs. Quite the contrary. Cereal fattens them up.
"Adult" formula dog foods merely switch the ratio of meat to cereal. They are more cereal, less meat.
Some of my opinions on dog foods are from my 3rd year of college, in the animal science classes. We studied how the various animal feeds are made, and what goes into them. We watched the various feeds being made. If you think I'm picky about what I feed my dog, you should see how fussy I am about my own food. Working in restuarants for 30 years, I no longer eat in them.
Personally, if I'm going to pay for dog food, I am getting more my money's worth if the food is mostly meat[meat is the main ingredient]. If I feel the dog needs more cereal, I can give bread or bisquits, not pay for a poor grade food. The price difference is small, 3or4 dollars a bag.
As to brand, again, this has only to do with ingredients. I am not impressed with silly meats like buffalo and duck. Chances are, with the exotic meats, they are a by product of an industry somewhere and the opportunity is likely larger that they are unregulated for contaminants. I cannot see duck farms for dog food. Duck is a very red meat, I would rather feed it to my dog than eat it myself, I just would not pay more than beef or chicken prices for it
I like Nutro Ultra for the acidophilus, which prevents loose stools, and aids digestion. Unfortunately, there is no panacea among dog foods. Depending on what you are feeding for, is how you should choose your dog food. The puppy formulas do not contain condroitin and glucosamine, so if the joints are my concern, like in Jawlaw's case, I would forgo my protein for the addition of the cond/gluc, which are available as suppliments, but simply too difficult to administer daily, on a long term basis.
As far as skin goes, the Nutro is GUARANTEED to improve skin and hair.
I have no health problems in my dogs [for generations, now] and am feeding Nature's Recipe puppy, and recently have experimented with a
house brand from PetSmart.http://www.petsmart.com/global/product_detail.jsp?PRODUCT%3C%3Eprd_id=845524441776340&FOLDER%3C%3Efolder_id=2534374302025907&ASSORTMENT%3C%3East_id=2534374302023689&bmUID=1129649194641 The reason I don't recommend these foods is that you are feeding smaller dogs, and can afford better quality food, which I cannot. Whereas, my last 3 litters of pups ate Nutro Ultra until they were almost a year old, my version of "adult" dog food is a cheaper puppy kibble. I still afford them the puppy kibble, though. Were I in dire straits for money, the adult formulas, and costco brands, would appeal more.
I recommend what I think is best for each individual situation. If I thought you were poor, and had 4 large, grown dogs, with no health problems [gee, you would be me], then I would advise something else. As it is, I recommend what I know to be the best food for each person asking, my advice costs me nothing.
Oh, I have read all the fancy labels on all the foods in the pet stores[yeah, I have way too much free time on my hands], and we have some dang big pet supermarts here in Pasadena, California. If I were suitably impressed with any of them, I would recommend them, too. Just overall, I found them to be silly, hyped up formulas with no overall merit.
I do like Dick Van Patten's Natural Balance for my cat. But she's a cat I think they are meant to cost more...