It's important to look at the first 5 ingredients on the label. I'll update this page with more specific info soon, but in the meantime here are a couple of good sites that will help you rate the quality of different brands:

This is a comprehensive, unbiased site with up-to-date dog food info, along with reviews and ratings:

http://www.dogfoodanalysis.com/

This Dog Food Rating Calculator was created by dog trainer Rosana Hart:

http://www.doggieabcs.com/dfc/index.php