Joey breeder recommended Biogroom products, and recently Petsmart started carrying them, so I like them even more. You can get a sample pack from the manufacture that includes, puppy shampoo, regular shampoo, oatmeal shampoo, and conditioner. I use the regular shampoo, and conditioner, and a few of their other grooming products as well. Here's their link, just click on "contact us" and ask for a sample of the products, it's free, and they are very concentrated, you add 4 parts of water to one part of the product before you use it.
Bio-Groom - Exceptional Pet Care Products for Over 30 Years I've tried different shampoos, and haven't found any I like better, I think as long as you are using a quality shampoo made for dogs, you will be fine, dogs have a different pH than human hair, so human products will leave the hair looking fried over time. I think using the wrong product can damage hair, but I don't believe that there is any magic product that will make dull hair look shinny, it's mostly genetics. Mainly you want a shampoo that safe, doesn't irritate their skin, or hurt their eyes, and is the proper pH for their skin, oh yes, and smells good too.