I am a born skeptic and although I am not a breeder I would feel uncomfortable placing a puppy into a home when you 1: haven't been able to meet them or 2: haven't been "vetted" by someone you know. It is so easy for a breeder to sell a puppy on a spay/ neuter contract but hard to enforce once the puppy leaves you. People can make themselves seem like exactly what you want until they get what they want.
I'm also not a breeder, but have friends who are. And I have seen this equation from the other side, twice as a puppy buyer (in both cases I visited, met the parents of the pups, had conversations with the breeders, etc.) and three times adopting older dogs. On one occasion the dog was shipped to me from Washington State…...but that was set up between the breeder in Washington who was looking for a home for a returned dog of hers and a breeder I had previously purchased a pup from, and who went with me to pick up the dog at the airport!
I think it is best to have personal contact if you can, but you can get a fairly good "feel" for people by talking to them. Internet may work for an initial connection, but I would want telephone contact at the very least. I agree with Chealsie508 that "People can make themselves seem like exactly what you want until they get what they want." My close friend who breeds Pyrenees has had situations that seemed ideal turn out to be anything but, and on other occasions placements that she was a bit concerned about turned out to be just great. When in doubt, going with your instincts may work, but not always. No guarantees, and it is very difficult to enforce contracts once the dog is out of your hands.
Once upon a time I thought I might sell a horse or two. Nope. Couldn't do it. Still got 'em, and they will die here. Glad I never bred my bitch! 🙂