Between these two it's PS4 all day for me, I've stuck with Xbox mainly for Gears Of War but this Xbox One sounds like no fun whatsoever.
I only really play online nowadays and Gears is my favorite, but I'll be content with Battlefield 4, Killzone and Planetside 2 on PS4.
PS4 is not a sale for me yet though, check out the Steam Piston... it's looking like the console killer, prime objective is gaming, and it'll adapt to evolving technology. They're making several types to fit people's budgets, and how far you want to go with performance.
It's a gaming PC in a little box, made for your HD TV. As someone who wants a console for games and games only, that is very enticing. Within two years, it'll be massively outperforming the new consoles you'll be stuck with for the next 5-10 years, it'll get better all the time, and you don't have to be a nerd to operate it like you do with a computer.