Thomas Coupling has told us of the long wait for CAA approval for Police Pilots to use NVG's. The practice in the past was for the non-pilot crewmembers to use the devices and the pilot to use the MK I eyeball.
This video shows the minor and insignificant difference in vision between the two methods.
Does anyone have any doubt as to the value NVG's for night flying? View the video and then ask yourself that question again.
http://www.henry1.com/nvg/NVG%20Lost%20Hikers.wmv