The Camcorderinfo page sums up most aspects of video performance. They found that color accuracy was no better than the competition, they were “fairly impressed” by the motion performance, and it did better than the others in low light, but for sharpness it was found to be weaker than the Panasonic GH1 and Canon 5D Mark II. Make sure you go to the linked pages at Digitalcamerainfo.com that go into more details, as they also compare the performance relative to some video camcorders as well.
While the Canon 7D's sharpness numbers aren't that bad, they definitely are lower than some consumer HD camcorders are capable—specifically in bright light. The Canon HF S100, HF20, and JVC GZ-HM400 all did better than the 7D in our video sharpness testing.I wish that in the charts where they compare performance they had included one or two video cameras, rather than just the GH1, 5D Mark II and Nikon D5000. While it's interesting to know how the DSLR cameras compare to each other, it would also be helpful to see how they compare to true video cameras.
One other thing I should note is that they used the 28-135 f3.5-5.56 kit lens for their sharpness tests; at least in the still comparison, so I’m assuming they did so for the video part too. I’m guessing it’s taken as read that with video, the performance of the lens isn’t going to drastically alter the results for video sharpness.