"Good food" is extremely relative, especially if your pet has a medical issue that requires a specific diet.
For example, my dogs are currently on a low(er) protien, low(er) phosphorus food to see if I can get their kidney values to normalize. The food that I was feeding them and still highly recommend is now a "bad food" for them.
My cats are currently in a grain free/novel ingredients, low carb, low phosphorus, low(er) magnesium food for a food trial and for urinary health for one of them. The food they were doing great on before is now a "bad food", and many other popular "good food" brands wouldn't have worked, either.
So my question would be, what diet does your vet want your dog on and why? (Ingredients? Fiber content? A specific vitamin or mineral concentration?) Then look for an over the counter food that fits that requirement and your budget.