Kelpies or Border Collies? what's the best dog for working stock

I have been listening to some Australian stockdog people lately and I have been trying to get a handle on what it is like to work a dog in Australia..what the work requires of a dog. I like Australian dog people because they are very practical. I spend alot of time breaking out my dogs and putting extra tools on them. I know that sometimes we get into situations where a dog could get hurt or killed. but those situations are rare for me and my dogs, (once or twice a year maybe). but if I was in Australia with my dogs, they could die from heat, snake bites, stock, poison and a multitude of different things!! so the attitude and expectations from an Australian dog trainer/handler have to be different to us here in the Northern Hemisphere