The video quality from the FC40 camera is not as good as the Phantom Vision camera. How do I know? I lost a Phantom Vision (don't ask... I still hope to find it...) and I bought a Phantom FC40 as a replacement. The FC40 has been out taking video of rooftops but has not yet found the Phantom Vision.
Anyway, a few comments comparing the Phantom FC40 to the Phantom Vision:
Phantom Vision: $1200
Phantom FC40: $500
Vision camera: higher resolution and better quality for both still photos and video.
FC40 camera: less distortion than the Vision camera.
The FC40 camera has less shake than the Vision camera. I presume this is due to the stock mounting arrangement being more effective at isolating the camera than the stock mount of the Vision. However, it seems to me that the relative smoothness of the FC40 video is more than just the way it mounts to the copter. Even when I just hold the tiny square in my hand and shoot video, the video is more steady than my hand... it doesn't jump around with small movements.
The FC40 camera also has 10X digital zoom, a very nice feature, although the more you zoom, the fuzzier the picture.
The wi-fi range of the FC40 is significantly less than the Phantom Vision. You still have remote control of the copter for hundreds of feet after you've lost communication with the camera.
I've tried, with no luck so far, to bind the FC40 camera to the range extender that was included with the Vision. I've been told it can't be done.
The tiny FC40 camera can be easily removed from its mount, stuck in your pocket and used as a halfway decent video camera, although you're shooting blind. In order to take stills, use the zoom and have a viewfinder, it can be connected to the iPhone FC40 app, which is entirely independent of the remote control for the copter. In other words, the camera can record "aim and shoot" video without being connected to anything at all, and it can perform all of its functions if connected to only an iPhone.