Fed my weimaraner Purina One up until about 3-4 years ago when the Purina treats (chicken jerkey treats that were made in China) were making dogs sick and they wouldn't do a recall. A friend of mine ended up losing her lab after feeding her the treats. Vet had no explanation other than it could have been the treats.
Anyways, it scared me so I switched to Blue Buffalo, and the change has been amazing! Brighter eyes, better coat, and she doesn't eat/poop as much.
I know it's more expensive, but the bag lasts longer since she doesn't eat as much. I guess it equals about $10/week, and she's a big dog.