Definately westbound for all the reasons mentioned above. If I am shelling out the big bucks for an AONE ticket, I want to enjoy the experience as much as possible.
Plus, being based on the U.S. East Coast and a European/Middle East AONE buyer, westbound allows me to do the European and transatlantic segment in one trip (can be as short as two days if need be) and still have 2/3 of the ticket left to complete at a more leisurely pace.