To me, poorly bred Shelties look weedy. Their coats aren't luxuriant and tend to be too soft. They just don't look right. That said, the tendency now to breed for heavier bone in show dogs just isn't all that attractive to me. Shelties should be balanced and medium dogs, not bruisers. (I'm not a breeder, and I don't show in conformation, so I'm probably wrong about some of this.) The biggest difference, IMO, is in temperament. Shelties are supposed to be reserved, not throw themselves at strangers, radiating "I love you! I love you!" They ought be active and athletic, not hyperactive. They aren't goldens. They aren't JRT's.