We have a black tri Aussie male who'll turn 1 year old tomorrow! He's great with our other dog, smart, affectionate, energetic (but not hyper, as some have said Aussies are), and not at all aggressive or difficult. We're going to start some basic agility training with him soon. If you want a good link to begin your investigations from, check out www.dog-play.com/agilityl.html