Not that we'd ever enter them in parrot shows, but none of my parrots could ever win. With the possible exception of Calypso, but that's only if looks were the only consideration (his personality among strangers is quite fearful).
Take Rocky. He does have this gorgeous green sheen -- he almost looks like he glows in the dark -- but he can't grow a decent tail to save his life! He is such a rough toy player, and a committed ground walker, that his tail is always breaking off. We joke that he has more of an amazon tail than a macaw one!
Here is a picture of a severe macaw that was recently surrendered to the parrot rescue where we volunteer. Look at that gorgeous, long tail! Then look again at Rocky. You can see it particularly well in the second picture when he's in his food dish.