One of the best examples, in my opinion, of the relationship between tenderness and flavor: you always trade one for the other. The cheek muscles of the beef are used for the majority of the day, even when the animal is lying down it is still chewing cud (the process of fermentation and efficient processing of the cellulose rich grass they eat).
So when you go to prepare your beef cheeks think long and slow to break down the connective tissue in the muscles. You'll be rewarded with incredible flavor.