I also say.. Do what works best for your dog!
I recently had to put Taycie on a RX Royal Canin diet. My vet suggested it to me because of Taycie is super sensitive. If food wasn't causing GI issues then she would end up with itchy eyes, tear stains, red ears..etc.
The changes in her were almost immediate! For now, this is meeting her needs so unless my vet decides to switch, we are sticking with it. She is also Tear Stain free as well! I am so happy with her new food! I think it has been an answer to her prayers