1. About 30" at the withers, give or take a couple of inches.
2. Same with any breed, it depends. Generally, they are good if exercised properly.
3. Over the age of 18months, about 5 miles daily, preferably more. Under the age of 18months, 7 minutes per month of age.
4. Pretty much anything you can think of. Hunting, agility, doggy dancing, guide dog, service dog etc.
5. Perfect family dog.
6. Great for working in groups, whilst they like other dogs company (I dont sugest these in single dog homes, then again..) they aren't very distracted when they have a group around them.
Go around, ask for recommendations, read into the breeder as much as possible, go see the pups ahead of time, make sure the living quarters are clean (keep in mind there will be pups runing around, so it wont be sparkling!), make sure the parents have had health tests (hip and elbow), check to see what vaccines the pups have, make sure pups have been socialized etc.