Nautilus on 21 November 2015
I think it will be close.But in the end PS4 will end up selling more.And I also think that Wii U will also do quite nicely, with the bundles and the lower price.
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
