I have tried all 3...but what it's going to come down to is what works best for YOUR dog. Honestly, what agrees best with my dog may not agree with your dog at all. I'd call the manufacturer of each and get one of their trial sized bags and see which one your dog does best on.

As for my dogs...
1) Solid Gold: They did okay on it, but a lot of the time the really didn't like it all that much.
2) Wellness: They did the best on this one. They seemed to like it the best, although sometimes it did give them gas.
3) Blue Buffalo: They wouldn't touch it. And honestly, after reading the ingredients, I thinks it's kinda overpriced for what it is. Also, if you look at the feeding guidelines, you have to feed a lot more of Blue Buffalo. Like it said to feed my 15lb dog nearly 2 cups a day!