Pick based on the games you want: (Score 5, Informative)

You seem to be leaning towards PS4 since you want Gran Turismo (they are Sony exclusive). It is a great system and Battlefront has some extras on it that you can't get on Xbox. Fallout also runs a little bit smoother on PS4, but you can't get Fallout 3 on it (Xbox One can play it now with backwards compatibility). I own all of the major systems and don't have a dog in this fight.