Unfortunately until both cameras are released and tested, everything is based on assumption that nothing will change. If video is your main passion, for what it's worth, one of nikons sample videos has been accused of having used Canon 5d2 footage in parts of their video. How true that is, i'm not sure nor am I prepared to really look into. If you also think of it, if i'm not mistaken, this is the 1st Nikon camera to support 1080 video? I think their flagship still had 720? I could be wrong, but basically this is canon's second generation of 1080p, not the first, like nikons, so it can be argued canon has had time to really fine tune the video from first generation to second whereas nikon is getting their feet wet, but with sony in nikons back pocket, i'm sure they are helping nikon catch up. I would probably guess canon has a slight edge in video terms, but probably not as much as one may think.
As far as camera functions, Canon has some advantages such as AF, FPS, customization of buttons and interface, High ISO, highlight tone protection, better mid range to telephoto line up of lenses, whereas nikon has advantages in wide angle lenses, time lapse, wireless commander, DR, super large files and MP... IF you were focused more on photography, nikon has a nice range and tonal range, however the files tend to appear flat and may need more post processing to add contrast and give your files that "pop" it needs to really shine... Canon has more pop, more contrast, more color range, and may need less post production work to get that pop, but it doesn't have more technical range, but in the end, your clients chooses pictures based on emotional and overall impact, not on which has more tonal range.
If your choosing video, it is canons second generation on 1080 HD but nikon also has sony's technology to help even the playing field. While I would want to think canon has an edge there, lets call it a wash for now until further tests are conducted.
Overall systems, Nikon has better wide angle (landscape), Canon has better mid range and telephoto (portrait) lenses... Flashes are debatable and almost a non factor if you get studio strobes. As far as the two cameras, they are too close to really call, but I would wait until you can hold and play with the 2 cameras in the store... If one fits in your hand better and is easier to use, that could be more important than any lab test can ever test. If you choose a camera and it's awkward and you miss a split second shot, is it really a benefit? If your this torn, wait until you can play with both cameras side by side before you make up your mind or you will never know.