Its a decent aircraft. I flew ORD-LHR earlier this year and it was an enjoyable flight, mainly because the service was quite exceptional for coach.
Legroom was not a problem in an aisle seat, but could be an issue for a center section. PTV's were an annoyance since they kept running at the empty seats which distracted me when I was trying to work. I'd much rather do without them.
All in all, I prefer AA's MD-11s, but the 777 is definitely a step up from the 763s and A300s.
"The A340-300 may boast a long range, but the A340 is underpowered" -- Robert Milton, CEO - Air Canada