I thought it was also very interesting that the Oculus Rift guys said that the cost of including an Xbox One controller was negligible. So that $15 estimate seems realistic to high, almost.
I am surprised that the difference between the PS4 controller and the Xbox One controller is estimated to be so small. Either that touchpad button, gyro, led, speaker and microphone are really cheap to add (which I can believe actually as they are all extremely common parts nowadays thanks to cars, phones and laptops), or those rumble triggers are relatively expensive.
And yeah, I wanna bet that they cost Microsoft and Sony less than this, probably a little under $349.