From what i have seen so far, X-Box One seems have to have locked frame rates at 30fps. Also PS 4 has a better Memory bandwidth and hence, a better overall performance. It's a tough choice really both provide certain goodies which the other don't, but when it comes down to raw gaming i would go with the PS4. With Black Friday approaching i think it would be your best bet. Though even if you go with the X-Box it's still a win win, you won't really notice the difference in the games unless you really sat down to check out the differences, and that would be pointless because you are buying the box to play and not compare . So in the end choose what your heart desires, both answers are correct in my books!
Edit 1: You can choose what your friends are buying so you can co-op.