Honestly, I think if your dog does fine on Nutro, why switch? I mean, if money isn't an issue, switching to a higher quality food is nearly always a better idea, even if they're ok on a lesser quality. But if money is an issue, and your dogs have always done well on their food (even if it's as "bad" as Ol Roy), don't beat yourself up over it.

I briefly fed Nutro years ago, but found it too rich. Loose stools to diarrhea , etc. My vet doesn't recommend it at all. My sister in law just recently switched to it, and I will forward her this information so that she is at least somewhat informed. Her three have been eating it for about two weeks or so, but she can keep an eye on them, just to be safe.