There are more differences between NW and CO on their first class.

CO serves unlimited HOT bread with at least two choices of bread, NW serves one cold dinner roll.
CO serves meals as you are in the restaurant: salad plate first following by entree then desert. NW serves in one big tray like eating in the cafeteria.

And the MAJOR differences: the attitude. CO's crews make you feel they want you fly with CO. One recent trip after September 11, the flight attendant addressed the customers before landing: "We are really honored that you choose to fly with us today. You show your confident with us by flying with Continental....", afterwards she shook hands with everyone and thank each customer. NW's crews are not bad, but they are just like other airlines' employees: "Just doing their jobs".

I fly often on CO, NW, AA and AW. I can tell you CO's crews have the best attitude. They want you to come back, and they make sure you enjoy flying with CO. I really respect Gordon Bethune. If you had flied with CO in the early 90's, you know what I mean.