There are two types of herding dogs. The MAS is a representative of the loose-eyed type, which works closer and stays upright. It is one of the few upright-working breeds still bred for livestock management in North America. The MAS was developed to be a tough, responsible, general-purpose stockdog capable of accomplishing most herding tasks. They do not possess the intense hypnotic focus, obsessiveness, and hair-trigger reactivity of the strong-eyed breeds.
Probably the most often-remarked differences between MAS and some other herding breeds are their natural protectiveness and loyalty, and their 'off-switch'. When there is no work, a MAS prefers to relax at your feet, not run down to the fence and stare at the sheep. Many owners owe their life to their dog putting themselves between them and danger.
MAS are exceptional at moving large flocks and herds, at pen and stockyard work, and at flushing out stubborn stock in heavy brush which a person on foot or horseback cannot penetrate. However, if you are looking for a stockdog for specialized work at the outer limits of what stockdogs are capable of, such as competing in international-style sheepdog trials, you may not want a MAS. If you are looking for a sensible ranch or farm hand who will take responsibility for livestock chores, and be your best friend and guardian, then a working-bred MAS might be for you. MAS do not "live to work" like Border Collies; rather, they live to please you in anyway they can.