Prefer AA you reckon,
QF A380v AA777, from a passenger perspective in any class, 380 is much quieter, Economy class 380 vs 777 at 10 abreast............380 any day!
Business 380 vs 777 is closer,but as long as you have a centre aisle no need to step over fellow passenger, id go 380, First Class 380 vs 777 also close, again 380 quiteness wins the day for me!
Let alone the average age, and attitude of an American Flight Attendant!!