I've been in the pet food business for over 30 years and have seen and heard it all. I also have two good friends who are PHD's of animal nutrition who actually formulate pet foods as their job.
At the end of the day, better dry foods have more meat in them and that makes them cost more. The ingredient quality can also vary, for example you can buy all sorts of grades of ingredients at different prices so the question is does the company buy based on price or to a quality standard.
Foods like the oft mentioned Taste of the Wild have more meat and use decent quality meats. That food is made in a plant that also makes many other brands and all levels of food quality.
Use Dog Food Advisor to rate brands, it's quite good and accurate.
Philosophically, you have to decide if you believe in (or care about) evolutionary principles or science when you look at nutrients. Evolution would dictate that a dog evolved eating foods in their whole form and that their body will recognize nutrients in that form best (and when those nutrients are delivered in accompaniment with the other stuff they "belong with"). Thus an apple has vitamins, moisture, fibre, etc all together.
Science would prefer you to use controlled nutrient. So a scientist would prefer to get vitamin C from a factory that made it in a consistent, synthetic, unaccompanied form. My two pals both are scientists and prefer the latter approach. Most of my customers at our specialty store prefer the evolutionary approach because they don't trust the big ag and marketing companies.
At the end of the day, all that really matters is whether or not the food is made cheaply or expensively. More meat = expensive. More carbs = cheaper. Home made is good only if you are very careful to get the balance of nutrients right. There are supplements that you can add to be safe if you make your own food.
I only feed my dogs higher end brands including Taste of the Wild, Nature's Variety, etc. I rotate feed so they get a different food every month. We also add canned meat to each meal (various dog food brands).
Hope that's more helpful than confusing....