Had an Aussie. Just wanted to add that, in my experience, causing trouble was inversely related to how much exercise the dog had. If you take 'em out and throw the frisbee every morning (walking is insufficient), you'll have a well-enough behaved herder.
Yeah our male BC was an adoption and I feel like he behaves more like an Aussie than a BC -- e.g. nips and barks at animals instead of the BC stare which is apparently a key difference in their herding behaviour -- and does the same for people. If he's really happy to see you? ... He'll nip a hole in your shirt. Something the female BC has never done.
But he's easier to wear out than her. Frisbee for a half hour and he's done. She's impossible to wear out. And thus you can see why they'd be invaluable on a sheep farm...
