I Love Aussies! And one of the keys to successful Aussie in a life is - exercise, exercise, exercise and obedience training and mental stimulation (as they tend to be bright, problem solving- or problem creating- dogs).
Typically they are a high energy dog that can be a hoot or an absolute pain.
Be ready to deal with the coat when it blows- they have some grooming requirements.
Some are small animal aggressive.
The ones that come out of working lines are often the most intense. Conversely, the one that come out of AKC lines are more apt to be coach potatoes.
So, it kind of depends on what you want. Are you used to a dog that lies quietly at your feet in the evenings or do you want a dog to go out with all day or train with?
And yes, the will herd, other dogs, horses, kids -
it's like a Retriever giving ya a ball to throw again and again and again :)
Hope this helps
Jackie
"I'd call him a sadistic, hippophilic necrophile, but that would be beating a dead horse. " Woody Allen