The qualities we look for in a working sheepdog

there are 3 attributes that I always look for in a young dog that will usually make my decision to keep him or sell him, early on.
I want to see power, balance and stamina. if he is missing too much of one of these I will most likely sell him.
often a dog can be very stylish and appear like the one to have, but it could often lack in one of these areas. sometimes a plainer looking dog might have all three in abundance, but be passed over becuase people dont see enough style.
Cap is the latter. alot of people consider him plain but I think he is the best young dog I have ever owned. (at 9 months there is time for more style to come too)
Alot of dogs that lack in one of those 3 traits that i mention, can often appear like the dog to have when we see them run at nursery level and indeed, they might make good open dogs but for me, they are not going to be ones that give me confidence at the next level up