Whats the best food brand for a Chihuahua?

We are adopting 2 female chis from the shelter, and they are both1 year old, both pretty averaged sized. I already have the 1/3 i in the morning, 1/3 afternoon, etc, but what is your best brand? What brand keeps the coat shiny and the dog i in top condition? And they are both longhair i don't know if this helps, but...... Thanks!