A very good new article comparing Xbox One and PS4 post Xbox One GPU boost!

[Zappykins]

DialgaMarine said:
I have to be a broken record here... I'm constantly hearing about how XBone has a whole plethora of features that the system can do that sets it apart from the PS4, but I still have yet to hear what they actually are... Can someone please, for the love of god, tell me?

A few of the Xbox One difference I came up off the top of my head:

Kinect - you can talk to your console - hey Xbox, look up this game/movie/tv show/actor/director/etc. Xbox.  In addition to 'pause' 'rewind' all by your voice, etc. (It really useful when you live with it.)

Motion Gaming included for up-to 6 players in the Xbox One, including heart rate:  http://www.youtube.com/watch?v=Hi5kMNfgDS4

Instant switching of games - demo: http://www.gamespot.com/video/xbox-one-interface-demo-6408651/

Playing a game or watching while waiting for an online game que to come up.

Can also be used to control your TV with you voice (or controller, or universal remote.)

Instantly recognizing you and logging you in, even if you switch controllers or places.

Skype, video conference included in every Xbox One, can be 'snapped' to the side even when you are playing a game.

The Controller - the One controller takes the best of the Xbox 360's then add some other features, lower latency, more battery life, the biggest advancement is 'feedback triggers.'   Having tried them I think they are going to be a great innovation in immersion and game feedback.  (The PS4 has a 'touch pad' which I understand will be nice for browsing, but a bit awkward to use in games because of it's placement.)

Many, many  app, I know Sony will have many, but doesn't seem to have anything near the level of Xbox's. 

Integration with you existing tablet through Xbox Smartglass your ipad, Windows Phone, Surface, Android Tablet, etc. (the PS4 can do similar but only with the Vita).

Integration with Windows 8 apps.

Xbox One will be running a version of DirecX 11.2, PS4 will be running OpenGL

Similar:

The both have sharing DVR Game features, Blu-ray, streaming, a form of friends, and gaming features.