Buy the Xbox One if That's Where All Your Friends Are
If your friends all play on Xbox One, you should strongly consider buying the Xbox One instead of a PS4.
There is no cross platform play, so if you buy a Xbox One you play against other Xbox players. If you buy a PS4 you play against other PS4 players.
I've built up a long list of Xbox Live friends who I play against and that is the reason I buy most of my games on the Xbox One, even though I own a PS4 as well.
If your squad of friends is on the Xbox One, it's a huge reason to buy an Xbox instead of a PS4.