in terms of capacity and efficiencies, the A346 is better than the B747-400ER, but gives the 777-300er a run for the money. <<the B747-400er has lost its competitive advantage to the A346 and B777-300er. airlines that fly the A340 (4 engine aircraft) instead of the B777 (twin-engine aircraft) probably lack the maintenance competency to maintain an aircraft to ETOPS standards.>> Last I checked, the 744 still had the 773 and 346 beat by 50+ in true PAX capacity. Also, I really doubt most airlines chose the 346 because their MX is not as good. LH chose 346 over 773 because of their relationship with Airbus, as they have one of the best MX divisions in the world. AC also has very good MX, and they chose 340 (though they don't have the cash to take them). I also think Virgin has pretty damn good MX, and they chose 346 to replace their 343 and 74Classic fleets(note that they are not using them to replace the 744s) Some airlines are taking both, like EK.