My dealer just quoted me $598 Cdn. To install the Toyota version, either from the 4Runner LE, or from the FJ Cruiser. Seems like a lot, considering how much cheaper they are aftermarket. (Yes, I know the Toyota part is more likely to be higher quality)
I had the rear sonar on my '07 FJ, and I have now been driving the Runner for about a month with only the rear camera. In my opinion, the sonar is much more effective, and safer, in that I am using my eyes and brain to back up the good old fashioned way, instead of looking at a stupid little screen. I don't think it is just a matter of getting used to the camera - I really believe the rear sonar is much better.