Not flown the airlines like Emirates or Singapore as they are not in our FF alliance. We have flown on most of the One World Partners and on Delta. However, the new American 777-300ER is the best we have found yet. We have done first quite a bit (thanks to miles) and the business class on this AA plane was better than first class on BA.
The business seat is a true lie flat seat and wider than the first class seats on their other configurations. It also offers more options on the seat control. I like my legs ALL the way up to horizontal on the foot rest and my back slightly reclined. As you would sit in a recliner. This cannot be done on the BA business or first class seat. Not a problem on this seat.
All asile seats. No one to climb over.One per side and then two in the middle. Sitting in your seat you cannot see anyone else and nor can they see you. All facing the correct way forward. If you are flying together in the middle you just need to lean forward to talk to each other not a problem. LOTS of room for your stuff this is a huge difference over many other planes. A compartment that is fairly large to hold whatever you like to have with you on the non aisle side. Plus a nice amount of "counter space" as well. The tray slides out easily not a battle to get it out of its compartment.
The TV is larger and on the demand system is larger. When selecting your choice the shows are shown with cover of the movie like it is on net flix. This gives you a sense of the movie immediately. You click on the picture to get more details. Great system.
Food I am sure was the same but it tasted better than I have had before probably because I was such a little happy camper it made everything better.
I went up and looked at first class it was a nicer looking seat and even wider but will be hard to get. Very few first class seats and I think about 50 business class seats. I am VERY happy with business on this plane and will make sure I get this plane any change I get.
For us it flys DFW to London. May be more on different routes I am not sure I just hope they get more of these planes.