It really depends on the cat and what you actually see in the results, like the quality of their coat or how energetic they are. Premium brands like Orijen have better ingredients and less filler, so yeah the food is actually different, but if your German Shepherd is already doing fine with what they're eating, you don't necessarily have to spend more - sometimes it's more about marketing than actual results. What really makes a difference is if you notice digestion problems, allergies or a dull coat: in that case yeah, trying something more specialized could help, but you'd be better off asking your vet who knows your dog instead of trusting random opinions from people at the park.