Kinect is a big feature/accessory for the Xbox One. Microsoft has been talking it up since debuting the console and even ensured that every Xbox One sold comes with one (which is possibly the reason for the price difference between the PS4 and X1). Similarly, voice commands are expected to be a big part of using the Xbox One.
The Playstation 4, on the other hand, does not come bundled with a PS4 Eye camera – it’s something you’re gonna have to buy separately. Sony also seem to be less focused on integrating the device with the console system, at least at this stage. While the Xbox One with Kinect can handle a multitude of commands, those that the PS4 and Eye camera will recognize are pretty limited.
For instance, you won’t be able to turn on or “wake” your PS4 from standby mode using voice nor will you be able to control media functions (like in Netflix). We do know however that you’ll be able to turn the console off using your voice and also launch games.
Of course it’s highly unlikely that Sony won’t improve on integration between the two via future system updates. Whether it will be able to catch up to Microsoft (and also encourage third party app vendors to make use of it too) remains to be seen.