Which side are you on? PlayStation or XBox?
Why not both! ... No seriously, I have both the Xbox One and PS4.
If I had to choose, I'd go with the Xbox One - it's not just a gaming device, it's an all-in-one entertainment bundle. With the ability to control the TV among other things, I can use just my voice to get to any game I want and even start watching StarHub TV!
The Xbox will also be getting loads of exclusive games and titles soon, and hands-down has the best multiplayer experience honed over the years.
Edit: I almost forgot... Halo 5 and Master Chief Collection! *le gasp*