No Border Collies here but Shayna (Cali) will be able to tell you all you need to know.

My cousin has two borders though. They're pretty typical of the breed. BCs need exercise. A 5 km run could be considered a joke to them. They're very intense dogs but SO intelligent. They thrive on work. If there's no work for them, they'll find it on their own. Because they're so intelligent and willing to work, they're excellent obedience dogs (along with agility, herding, flyball, etc).

But since you're getting a mix, maybe you'll get lucky and get the intelligence without the "ball, go, ball, go" personality.