The_BlackHeart__ on 18 November 2015
I will recommend both. But it will make more sense to pick up The Witcher now that %99 of the game breaking bugs are fixed.
Fallout 4 does not have game breaking bugs as far as my gameplay goes, but there are a few anoying instances that will probably be fixed in the next few months.
So, what I'm saying is: The Witcher 3 now and Fallout 4 in January 2016.
