I believe that the whole "Angus" thing is a genius marketing ploy. When growing up in GA is seemed to me that the farms were split 50/50 dairy and beef. The majority of beef farms were Angus followed at a distance by a breed called Polled Herford, there were some specialty farms that raised Limousins and Charolais. Angus and Herford were picked because of their stocky build, good health and growth rate. So I would be willing to bet that 75% of the meat at the meat counter is Angus, they just package some differently and charge more for it.
Myths about beef cattle IMO
Grain fed means they eat exclusively grain. I have never seen American beef cattle that were not allowed to graze. I actually believe it is unhealthy for them to eat exclusively grain not to mention expensive. All cattle are fed scientifically designed mixtures of grains/minerals/nutrients that provide rapid growth.
Certified Angus is better. Like I said, a mojority of meat is Angus already, some better, some worse. Is it worth $2 a lb extra to have somone go "Yup it was Angus"
Beef in fast food resturants is good. Well I am sure it passes FDA standards but it is junk meat. It is made form old used up dairy cows, odd breeds that are not known for beef production and scraps that are unsuable for whosale meat. 100% beef means that it is made from anything in, on, stuck to, stuck in, or around the cow when it is processed.