Careful with the dogfoodanalysis website... while most show an accurate representation of the foods, some can be a bit biased by the boxer forum that created it.

http://www.dogfoodproject.com/

You can check out here and read up on certain ingredients/foods and make an informed decision based upon your research. Because the puppy was on a low quality food, I would do the slow transition, and expect some bumps on the way to a richer food. But by all means, please switch the pup over to a richer food. He will benefit in the long run.