there is no "best for puppies" just "best for that particular dog".
if you are getting your puppy from a responsible knowlegable breeder talk to them about what they feed and why. most breeders keep a puppy (maybe not every litter but once in awhile) and thus have seen their puppies grow on a food - so they know what works best for their dogs. At a minimum i would keep the puppy on the food the breeder is feeding for a few weeks/month and if you are unhappy with results, you can research and change at that point. I wouldn't be in a hurry to change the food unless it's a crappy breeder feeding whatever is cheapest.