Virgin is looking for a very good deal on new aircraft and to lock in very low prices for future aircraft for fleet renewal and expansion. This order is all about price - even if VS
concluded that the 773ER was the beter performing aircraft, the better priced aircraft will win the order - its likely that many of the A346 aircraft will end up on transatlantic runs and services from London to South Africa, and for these routes, the A346 is just fine and the marginal advantages that the 773ER may offer are not very important. The four engine thing, in my opinion, is nothing more than silly marketing nonsense put forth by media-happy Branson to counter BA
's wide-spread use of big twins on long haul routes.
I really hoped that Boeing would secure a big order from Virgin - while it still can happen, recent information seems to indicate that Airbus will get this order. Boeing, at the last minute, can always cut prices and make a last minute proposal to Virgin, but this kind of behavior has not been typical of Boeing in recent years.
This competition will go down to the last minute, I really dont have much faith in press releases like this one as such items are usually only put out there to put pressure on the manufacturers. Only when there is an offical order from Virgin can we be sure if its the 773 or A346.