To sum it all up-
Every cat is as different as every situation. I agree that the best is a pet/vet brand, the next best would be a name grocery store brand, and the ABSOLUTE worse is an off-brand. I also understand that there are some situations in which a full belly of anything is better than an empty belly. I almost always give Iams, but lately have fallen on some hard times and have had to switch to name-brand grocery store food. I forsee having to downgrade to an off-brand from there in the next few days. But my other choice would be to let my cats go hungry. I have never had a cat that would tolerate any Purina variey, and I also read a book written by a pet nutritionist that said Friskies was the best grocery store food, so that's what I've been feeding for the past few weeks. But that's what works for me, it's not that I think Purina is inferior. Over the years I have occasionally fed strays or ferals, and they got the cheapest brand available, because I couldn't afford to feed the wild animals premium cat food, but at least they were not going hungry. So what to feed is a very personal decision, based on financial considerations, the animal's situations, and the animal's tolerance and preferance.