I have always spoiled my dog, she has only eaten grocery store bought dog food a couple of times and it makes her tummy upset, coat not as shiny, and a little bit more of a smell coming from her coat/skin. I usually keep her on
Natural Balance and it seems to do the best for her. But she just has a weak stomache and reactions to food she isn't supposed to eat.
My ex-girlfriend used to work for a vet and she says the thing to look at in the ingrdients is no by-products and not much corn. We researched a few foods and found that
Old Mother Hubbard foods seemed to be the best in terms of quality ingredients. The ingredients list is listed from most to least, so if you see corn or anything by-product on the top of the list, the food really isn't all that great in terms of quality. But that being said, I'm just a picky person anyway, but I have never met an animal that wasn't happy to receive food of any kind.
Hope this helps