To echo MatthewClement, AA really does have a competitive advantage with their in-seat power even in coach. I flew LGA-MIA on an older MD80 a few weeks ago, and even back in row 24 there were two power ports shared among three seats on my side of the aisle.

UA's power ports are sporadic at best, with most 777s I've been on being inoperative and only the 744s and 763s being reliable-- and then only in C/F. AA's commitment to its entire fleet in all classes of service is something UA ought to consider.