I have tried every dog food on the market and there are only two that I really trust for my beloved dogs.  One is Beneful and one is Eagle Pack. 

Both are full of nutritious ingredients that give my dogs energy and their coats shine.  If you really want to tell a good food from a not so good just feed it for a couple of weeks.  With a high quality your dog will show within that time as their coat will begin to really shine and look bright and not dry and dull.