Runt
Brute
I've had both runts and brutes over the years. The runts tended to have a better demeanor as well as less hip and joint problems, they also lived longer than the brutes. That's my experience.
If you have a reputable breeder that you trust.....leave the choice up to them. If they know what you are looking for in a dog, they are much more experienced than you at recognizing the potential for the pup to be what you are looking for. The breeder we used for our lab "matches" the pups to the homes....you pick sex and color and tell her what you are looking for....beyond that, after 8 weeks working with them and observing them, she chooses which pup goes to which home. We coudn't be happier with our lab....she is exactly what we were looking for.... from stature to temperment, drive etc. We had even asked for a chocolate and she convinced us that there was a black in the litter she felt would be a much better fit for us! I'm sure glad we trusted her judgement!!!
Good luck with your pup!
Chris
"Do not go where the path may lead,
go instead where there is no path and leave a trail."
Emerson