I would be wary of both breeders - the one you're going to see and the one you posted the site of. Being AKC registered or champion sired doesn't mean anything for one. Any breeder can register their litters with the AKC, it doesn't mean they are good specimens of the breed, nor that they are healthy genetically-wise.
A breeder that posts on breeder.net and doesn't have any list for their pups when they are 5 weeks old is a big red flag. A good breeder will make sure there are people interested in the puppies beforehand. A good breeder will only breed to improve the breed, not to make money or for 'fun'.
Sure, you probably don't want a show dog. But it doesn't mean you shouldn't be very picky about who you are getting your dog from.
Good breeders will test the parents for health issues before breeding - it includes hips and eyes, plus whatever health issues the breed can have. It is
very important that the testing is done. If it's not, it means that the parents could carry all kinds of genetic issues from poor breeding, and the puppies are likely to have them, too. Breeders that don't check the health of the parents before breeding just don't care that the puppies might end up suffering all their life, and I find it disgusting. And most of the breeders that post on sites like breeders.net are of that kind, ie, backyard breeders.
Another thing about backyard breeders - they don't care about whether the dog is a good specimen of the breed or not. So you could end up with a dog that doesn't look like a papillon, and doesn't have the right temperament either. Compare a show dog with a petstore puppy of the same breed, and you'll see the difference - well, it's the same with backyard breeders, who just take two dogs and breed them. Saying that the parents are of champion bloodlines, or that a friend of the family said they are good specimen of the breed doesn't prove anything either - the dogs need to be titled to make sure that they are indeed a good example of the breed.
I strongly suggest that you read all the stickies, especially
this thread, so you are sure to have a healthy pup.