Hard to tell. What I can say it absolutely certainty is that the decision will be made on purchase price and incentives added to sweeten the deal.
Oh, I'm sure the Pro-Airbus and Pro-Boeing factions on this forum will have valid arguments for and against each product.
But it will go down to price. There have been enough "defections" from one maker to another over the last decade to show commonality (spares or cockpit) does not feature high on the agenda in aircraft sales. So that is no longer a valid argument IMO.
In a sense, the real question is: Who is willing to discount and incetivise enough?