Hmmmmmm though call, but i think Tomb Raider is going to win this one.Mostly because its 1 year exclusivity, and will be marketed the hell out of it, while Fallout 4 sales will probably center more on ps4 and pc.
My (locked) thread about how difficulty should be a decision for the developers, not the gamers.
https://gamrconnect.vgchartz.com/thread.php?id=241866&page=1