For no technical reason, I'd go with Kroger. In the broad sense, "choice" is "choice" and "rib roasts" by any definition is great. Did you notice if CM's is Angus - they tend to carry a lot of it.
One thing is true - The "small end", ribs 9-12 are more tender and less fatty than the large end, ribs 6-9. Also, have the meat cutter remove the bones and tie back on for roasting - remove ribs (cook's treat) for easy carving. As the meat rests, "bones on" will hasten the cooking outside the oven.
Bone removal and tie-back was gratis at Albertson's a few years ago - no up-charge.