My main complaint about using a DSLR for video instead of a video camera is that there's no in camera image stabilization. I forgot how much I depend on that for a good handheld shot. It can still be done with the smoothcam feature in FCP, but that means cropping in -often more than I would like.
That being said, the image quality with interchangeable lenses and crazy ISO boost means beautiful crisp dynamic images even in really low light situations. Lighting exclusively with 100 watt incandescents works like a charm! Who'da thought. Making this thing incredibly versatile for low hassle setups.