... built-in ND filters ...
... And the native 16:9 sensor should limit some of the artifacting present in 5DII since it doesn't have to drop lines?
... Canon is apparently announcing some video products tomorrow (13th) - competition is good!
All good points!
In a camera with purely video viewfinder, no OVF, built-in ND filters neatly address the issue of sometimes wanting lower sensitivity and longer exposure times than the minimum ISO speed allows. And rolling shutter video has rather rigid exposure times, so this might be important far more often that with a focal plane shutter.
About artifacting, Panasonic makes a claim about "dramatically reduced video aliasing", and one big advantage is that the AA filter can be set with a frequency cut-off matched to the lower Nyquist frequency of the larger pixels of the 1920x1080 sensor.
Also, with only 2MP to read instead of 12MP to 24MP, the rolling shutter could be far faster than in DSLR video, so there is hope for far less of the Jello effect than with a digital still camera hacked to do video as a side job.
I would be pleasantly surprised if Canon moves into the `larger sensor dedicated video camera' market tomorrow, but here is hoping. RED might be seeing some push-back in a sector it has almost had to itself.