Whenever you play a video in the Video Application of your Surface you will notice a button that allow you to play the video in other devices.
This button appears in the iPad whenever it detects an Airplay device or server. In Surface that button is there even when there is not any device where you could play the video.
The Play To option in my case shows the two media player devices I have the WDTVLive and the WDTVLivePlus. As you can see they are not Microsoft Certified, but if you select one of them you will see this other screen coming:
And right after that...
The video is playing in my TV, something that the iPad will never do using a device that was not made by Apple or without having applied, installed or hacked a workaround. That's the beauty of Microsoft ecosystem. The total cost of everything needed for this trick is a lot less than what the Apple fan boy pays for his iPad and Airplay device, and that does not count that either WD device mentioned here plays more movies formats and have a lot more features than the AirPlay. Currently we have around 290 devices in the market to select from to use this feature included in Windows RT.