I am not an expert by any means. I am a new yorkie owner, but after quite a bit of research I decided that wellness made a good food. I have tried it with my puppy, but he doesn't seem to like it. He hardly eats anything. I have tried sticking it out, but I think I am going to switch to Merrick. I bought some for my Golden Retriever and Harley is always trying to steal it, but when I take him to HIS food he won't eat it.
I talked to someone at our local pet store and he said he likes Merrick better because they freeze dry all the veggies and put them in after everything else is cooked, so the good stuff isn't cooked out. I am hoping if I switch to this he will actually eat it! I am hoping he doesn't just want the other food because it doesn't belong to him.
I think that Wellness is probably still a good food though.I hope this helps you in your decision. Sorry it is so long.