I met a lab this week who came from hunting lines, his sire is in the hall of fame or something. :/ Anyway, the dog was NUTS... NEVER stopped moving, had so much nervous energy he literally made me dizzy. Responded quickly to cues, it was clear he'd been well trained, but he had NO idea how to settle. His owner said that she's never seen him lay down except in a crate.
She - his owner - likes that about him, but he'd drive me CRAZY.
So, be careful, know what you're looking for and meet some examples of the breeder's dogs before you get one!