There are 2 interesting examples here of video from the Nikon 300s and Canon 7D specifically under artificial lighting conditions at night and the wave type issues that appear on the Nikon but not on the Canon 7D. You can see this near the end when the person is filming a shop with the Nikon 300s and moving down towards the pavement and back up. You see the wave effect for a few seconds before the camera seems to adjust and the video comes back to normal.
It seems the Canon 7D may have one up on the Nikon here! The below example from the Canon 7D is just amazing !
Think this just convinced me to save up for the Canon 7D for Christmas! Note that the rig used for the 7D is very impressive but cannot be considered a reason for the difference in quality of the video if you were wondering... He has added a lens hood / matte box, viewfinder and microphone and uses tripods, other stabalizer gear and last but not least this was shot at 1600 to 6400 ISO!
I can't see any information about the types of lenses used which will have a major impact in comparing the two cameras.
It is a cool video Dan Chung. I like the way he uses 'effects' that could be considered as inherent issues with a camera with video capacities...
If you look at the DOF for each video, the nikon video is much more in focus which tells me the video was shot at a higher f-stop value. The canon lens could have been a better lens (f2.8) because you can see in the video very easily the objects and people close and far away are out of focus.
I think it is a 50Hz or 60Hz issue. Try filming the same thing at the same time with both cameras. And with samme fps if possible. Btw. I am thinking about buying the 7D or wait for Nikon D800.