I stopped using all Purina brands when Proctor and Gamble bought Purina.
I was unaware that Proctor and Gamble had bought Purina. But they do own Iams and many folks refuse to use Iams for that reason.

I think either are ok, frankly. My vet has always contended that Purina does more research on pet food than any other company and that is the brand he uses for his own pets. My Mimi, who is 14, and very, very small, ate Purina Kitten Chow for years and thrived. She and Butter now eat Flint River Ranch because Butter was having some skin issues on a Purina product (Pro Plan), and it was suggested that I try a food that didn't have any fish in it. His problems have cleared up completely, so I'm sticking with what works.