I currently have ~ 6 month old GSD pup who I feed Orijen Large Breed Puppy. I was talking to a rep from Champion, who also has experience working with other brands (Wysong, Vital Essentials, etc.), and he gave me the recommendation to grab other Champion foods -- 6 Fish, Regional Red, Ranchlands, etc.., and feed that every other day in combination with the LBP. He believes that a puppy isn't going to get all his/her minerals from just one source of protein, so mixing in Red Meats occasionally in conjunction with Chicken/Fish will balance out nutrition.
So what I do is buy the largest LBP, and then a smaller bag of Orijen or Acana mixes, and a couple days a week, I substitute one of my guy's cups of LBP with Orijen Regional Red or Acana Ranchlands. He doesn't have any digestion issues, and he seems to do really well with this rotation. I sometimes have to get him to back out of the pantry where I keep his food after he eats because he tries to go back for seconds. His coat is great, and his energy is thru the roof. I think he also puts on good weight through out the month, his is very athletic and agile.
The rep really didn't push me to Champion, I was already feeding it and he assumed I was comfortable with the company, but I think his rotation suggestion was broad, so any company's selection of food would work. He even opened up and said I could do Raw this way later when my pup is older - do dry in the morning and Raw patties/feed at night. But he told me a good thing also -- "If your dog has energy, is fit, and his/her metabolism and digestion is good, there is nothing to worry about."