Daiseiko,
I regularly travel on an AA 763 between MAN-ORD and to be honest I find the coach cabin quite comfy and if you are in coach with one world status see if they can get you in the coach mini cabin I find it to be less noisy and a little more private in there.
As mentioned the entertainment is a little bit of a let down (with overheads only) so this might be the perfect moment to buy a personal media player ^

If you’re in business you should be fine it looks nice enough although I've never been able to get myself in there.

Enjoy your trip.

Jamman.