Check out a writeup of using the 1DC on set with the Teradek Cube on the Wonderblog:
One of the most exciting non 4K features of the Canon 1DC is the HDMI mirroring feature which will let you plug in an external monitor or recorder while still being able to use the camera's LCD screen.
The Teradek Cube has been one of the most important tools in my kit allowing me to light weight hand held rigs and still send a wireless signal to a client's iPad. I don't like EVFs and up to now I've had to limit using the cubes to cameras like the C300 and Alexa. Now with the HDMI feature I am able to still use my guerrilla hand held tactics while sending a wireless feed.
For now this feature is exclusive to the 1DC but after a firmware update in April it will also be available to the 5D3. That opens up a whole new world of monitoring options.
I firmly believe the Teradek cube is a perfect addition to shooting and know with HDMI mirroring it can play a huge roll in getting the most out of your DSLR shoots without having to build a large rig.
A special thanks to:
Tony Maggio - Camera
Daniel Lachman and Justin Sharp - Editing
Ben Clancy - Music BenMadeThis.com