Yep, it's expensive. But its unique selling point is that it keeps all app functions, adds a separate tilt control using the "spare" 7th channel accessed from the back of the TX, allows the camera to point straight down, is self-contained and requires so additional power supply or soldering to tap into the aircraft supply and it seems fairly straightforward to return the Vision to stock if you ever need to...
I guess the first real-world user reviews will let us know if they feel it's worth the money! At a total cost of about $1800 for Vision plsu this gimbal it's pretty much the same total price as a non-Vision Phantom with 2 axis gimbal, a GoPro, an FPV rx and goggles/screen and telemetry downlink, except you can't control the GoPro from a phone app from 700ft away...