To me an ace is one that is not going to be beat. They may not be the best at everything but they are very smart and have an answer for everything you do. They dont waste a bite. Some dogs just bite anything like a tail or skin on the rib cage. Every bite an ace makes has a purpose. I've seen a good amount of very good dogs. One not on the list that made me say he is an ace watching him his last time out is Turbo.