My experience is that the equipment on CO is somewhat cleaner, but there's not a significant difference between the two. CO offers free meals in coach on certain flights. AA has buy on board. For me, it's not a big deal. I only sit in coach if I buy a ticket at the last minute and I don't do that anymore!

I can only share my experience and what AA has to offer has to be compared to the alternatives--the other carriers. Frankly, if you're an EXP, AA wins hands down. It's not even close.