It is so sad and frustrating that there is this extreme confusion with dog food. I'm not a professional dog nutritionist, but I've done my fair share of research, and I'm not saying just the opinions of people on this forum (though it has been a pretty good resource). I try to keep a very open mind, and not listen to bias opinions of people who are just in favor because other people are too. I've fed Orijen and Acana to my dogs with great results, I've seen friends and family switch their pets to Orijen and Acana with success and they'll never go back to the foods (Eukanuba, Purina) they were feeding prior. I've spoke with different trainers, a family that owns sled dogs/huskies, and even my vet, all who agree that Orijen and Acana are great foods.
My vet believes that Champion pet foods are a great choice. I actually left my last vet because I felt his knowledge was very narrow when it came to giant breed dogs (I had just adopted a Great Dane puppy, done a lot of research, and he didn't seem to know the different requirements a giant breed needed, so I went in search of a different vet), anyway my point here, that vet supported Science Diet and wanted to push it on me when my dogs had any type of ailment or itch it seemed "this will fix that, SCIENCE DIET!" I left. The vet I have now thinks Orijen is working great for my dogs, I didn't choose to stick with him solely on this, but he has a lot of knowledge when it came to Giant Breeds too so I trust his overall opinion. PLUS he told me that he sells Hills Prescription diet dog foods at their clinic, but he personally doesn't believe it's the best diet, he said "there are some situations where a dog does need a diet like Hills Prescription Diet, and it works well to fix certain ailments that dogs get, but it's not a life long diet, it's like a temporary medicine"...that really helped me understand, Science Diet has it's purpose, but it's not meant to be a diet. It's like getting an infection, and then receiving antibiotics, when the antibiotics are done, you don't go back and get more and take them for the rest of your life, it's temporary to fix a problem, THAT is how Science Diet should be used, not as an everyday diet. It's the same with doctors, some doctors take the approach of "you have Xproblem, this Xmedication I carry will fix it" instead of " you have Xproblem, if you eat more fruits and green vegetables that will fix your problem"...just different approaches, but I personally believe the second approach is more of a "natural health" way to do it.
I like to think of it this way. I'm not a "tree-hugger" but I do believe that there's so much going on in this world that people tend to forget where we came from and what is natural and healthy. Some people will argue that humans are capable of creating something BETTER THAN NATURE using science and studies (like Science Diet, it's backed by tons of studies proving that it's the greatest food for your dog), but when we look at wolves and their diet, we see that dogs are carnivores and need real meat to survive and most of all to THRIVE, not corn and grains. Ultimately I would grow my own fruits and vegetables, raise my own chicken and cattle, milk my own cows, make my own cheese, and grow my own wheat for making bread, I truly believe that is the way we were meant to live, and it's no secret that eating whole fresh foods is great for our bodies, why would dogs be any different? This is the approach I take to decide what's best to feed my dogs too, what is the most natural healthy way? How would they get what they need in the wild (aside from natural threats like limited resources/predators/natural disasters and such), they would eat fresh meat. How would we live without manufacturing plants that create processed foods? THAT is how it should be IMO.
Ultimately I think RAW is the ideal diet for dogs, people that feed their dogs a RAW diet are proving this all the time with the appearance, health and energy of their dogs. But this is the kibble section...sorry

. My point here was that, even though I think RAW would be better than kibble, I think Orijen and Acana are better representations of food closer to a natural diet than a lot of other kibbles. It's probably the closest you can get to feeding RAW without actually feeding RAW, still a processed kibble, but much better than some out there.
Dogs that get the runs on Orijen are probably being overfed, it's a very rich food, but still some dogs cannot handle it, and will always get the runs from it, in that case I've seen those people switch to Acana and have no problems with it. A lot of people prefer Acana to Orijen. I feed both.
Good luck. Whoa...I blabbed a bit here, sorry!