Fay was a very picky eater. After trying several brands of dog food, we stuck to 1/4 cup Pedigree Healty Start for Puppies (canned) and 1/4 cup Purina Por Plan- Puppy & Small Breed Formula (dry).
I also learned from my dog trainer that you should feed your pups inside of their crate, taking away any toys in it. This will leave them with no activity other than eating. Puppies get distracted easily and if not put in the crate they might eat just a little, go of to do someting else and they won't get the appropiate nutrition they should.
Using Iams, he doesn't like Science Diet at all. Very picky eater and I have to make sure I am getting something that both Morgan and Bailey like. My vet said it is right up there with the Science Diet so I am very comfortable with them on it. (He eats very little of this too, but eats more of the Iams than any of the other brands)