based on recent experience, what matters to Joe public travelling long haul.
Seat pitch
Leg room, especially under the seat in front, it's no good if the IFE is taking the foot space, as it did on a recent Delta 777 flight
Seat Comfort. Even if the seat pitch is right, if the seat isn't comfortable, it makes a very unpleasant flight! Same comment about the Delta 777, whatever it was about their seat design, it's about as comfortable as a McDonalds seat, and we all know they're designed to persuade people to move on!
Working IFE. It can be the greatest system since sliced bread, but if it's not working, then forget it!!!
Cabin temp. Too hot, or too cold is no fun at all for 9 hours.
Most of the other things are pretty much equal, but as far as I'm concerned, the above are things I will look at VERY closely in future, the 777 was a severe let down, it was supposed to be good, but it was one of the worst T/Atlantic flights I've had in a long time!