What is the main difference between the Phantom 2 and Phantom 2 Vision beside the camera?

For the most part they are. The most obvious difference is the frequency of the transmitter. The Phantom 2 uses a 2.4Ghz transmitter. The Phantom 2 Vision uses a 5.8Ghz transmitter. The reason for this is so the vision can use WiFi for FPV on phones and tablets.