Royal canin, iams better quality than whiskas?

Royal Canin does have corn, but less than the other two. And it contains better quality meat. Iams and Whiskas (at least here in the US) contain mostly meat by-products - that isn't meat, it's scrap "parts" that have been deemed unfit for human consumption. It's things like beaks, hides, tendons, spleens, intestines - you get the idea. While Royal Canin is more expensive, it's of a higher quality than the other two. I wouldn't call Iams a quality food at all.