I used to feed Nutro and switched them to holistic food and will never go back. I recommend anything very low in grain or preferably grain free. My dogs have done wonderfully on them. I feed Acana. Sam used to get chronic Colitis to the point the vet recommended we permanently put him on steriods, and when we switched him from California Natural to Acana he hasn't gotten Colitis since! I'm assuming it was the grain.
It sometimes depends on the dog. My brother used to feed Springen Innova Evo, listed as a six star on the site above, and for some reason he always had diarreah on it.

Blue Buffalo is probably the best pet store (petsmart, petco, etc) food I know of. I really haven't heard of Proseries.