From fsis.usda.gov:
Quality Grades:
Prime grade Image of Prime Label is produced from young, well-fed beef cattle. It has abundant marbling and is generally sold in restaurants and hotels. Prime roasts and steaks are excellent for dry-heat cooking (broiling, roasting, or grilling).
Choice grade Image of Choice Label is high quality, but has less marbling than Prime. Choice roasts and steaks from the loin and rib will be very tender, juicy, and flavorful and are, like Prime, suited to dry-heat cooking. Many of the less tender cuts, such as those from the rump, round, and blade chuck, can also be cooked with dry heat if not overcooked. Such cuts will be most tender if "braised" — roasted, or simmered with a small amount of liquid in a tightly covered pan.
Select grade Image of Select Label is very uniform in quality and normally leaner than the higher grades. It is fairly tender, but, because it has less marbling, it may lack some of the juiciness and flavor of the higher grades. Only the tender cuts (loin, rib, sirloin) should be cooked with dry heat. Other cuts should be marinated before cooking or braised to obtain maximum tenderness and flavor.
Standard and Commercial grades are frequently sold as ungraded or as "store brand" meat.
Utility, Cutter, and Canner grades are seldom, if ever, sold at retail but are used instead to make ground beef and processed products.
