He gushes about the video quality you can get:
I was able to achieve a razor-thin depth of field that would make a 1970s maverick film director proud. The colors, when properly white-balanced, were rich and full, and the dynamic range [...] went well beyond anything you'll get in a sub-$10K camcorder.
Points out the problems you might encounter:
You can set aperture manually with the Aperture Priority mode, but the camera still automatically adjusts ISO and shutter speed. To remedy this, exposure needs to be locked prior to shooting. [...] this is less a science than an art, and may take some trial and error.
And is upfront about the limitations:
...there's no microphone input; autofocus is disabled; full-quality video can only be shot in 5-minute bursts due to file-size limitations; and, as many people have pointed out, the rolling shutter of the camera's CMOS sensor can produce some queasy-looking vertical lines...
And then he proceeds to put it into perspective:
But none of these are deal-killers. If you want better audio, then shoot dual-system [...] Autofocus? It's far less precise than manual focus—especially on 35mm lenses—which is why manual is still the method of choice on movie sets. Need a shot longer than five minutes? Consider this: the average shot duration in most current Hollywood movies is around five seconds.
He's not even put off by the dreaded Jello-effect:
As for the dreaded "jell-o effect," there's a very simple solution: keep the camera steady (tripods are good) and stay away from whip pans!
There's a sample video clip too, which is definitely worth checking out. While you don't get a good sense for resolution, you do see that the camera can shoot a fairly wide range of subjects, and you can move the camera or have a moving subject and not end up with unusable results! Check the cool pool table shots towards the end of the clip!
So what's a video producer to do?
If you already have some Nikon SLR lenses, I think it might be a no-brainer. Buy the D90 and use it for special effects. If nothing else, it'll be a good SLR camera.
Don't have any Nikon lenses already? Don't need an SLR? I don't think I'd buy this camera purely for it's video capabilities. Even with the Canon 5D Mark II I'm not certain that people will be buying it just for the video capability (though maybe I'll be proved wrong.) But I am willing to adjust my view of the D90. Having gone from initial excitement, to complete disinterest, I now think it could be a fun little video camera.