hey i have a 14 week rottweiler puppy and he is the pickiest eater out there, i had him on nuetro ultra and he hated that i switched it to nuetro natural choice he hated that too!
now i am feeding him a vet recommended Hills healthy advantage ( all of them are large puppy formula) my question is what do you think of this food as i couldn't find it on your puppy food section.
Some puppies are just picky eaters... and Rotties seem to be inclined to be this way.
I wouldn't worry too much about what he likes, but simply choose a good quality food and give it to him. If he feels that you will keep offering him different food he will begin to hold out for 'the goodies'. It's your responsibility to give him good nutrition - but it's HIS responsibility to eat it :)
He may not eat as much as you would like (or much at all) to begin with, but nature won't allow him to starve himself and once he figures out that this is all he's getting he'll soon wise up. Pups of this age also tend to go through stages when they're hungry, and then stages when they're not. It's a natural part of their development.
The Hills foods are only stocked by veterinarians and I haven't ever used them myself. Although they are of a reasonable quality, they are pretty expensive for what they are - but if your pup likes it, then I'd stick with it.
Hope this helps some, best of luck!