I have to agree Science Diet isn't my favorite food for many of the reasons posted by wolfsoul. That said I will say I fed my RB terrier Sandy SD for years and he did fine. I switched him to Waltham (now Royal Canin) when he was about 8 and it was mainly because he liked it better. (I found pieces of SD lieing around his bowl, and the Waltham was completely gone!!). I've also fed SD R/D to Bear. I had a nightmare of a time trying to get weight off when I first adopted him so the vet put him on SD R/D. It got the weight off and he didn't have any problems on it. I now feed him Eukanuba senior and my other 3 get Canidae, but that's just a person preference. My opinion. SD is definately not the worst brand nor is it the best. I'd put it somewhere in the middle.