Like Courtney Mil, I was a QWI
However, there were differences between forces. On the F3, the carry-over of principles and ethos from the F4 (and some from the Lightning) made the course and outcome certainly not 'I' in any meaningful way. In that I mean that QWIs were assessors first and instructors a very poor second (In my view as a QFI / QWI) It appeared to be more about Image (The Red Coaster) and less about passing on the real gen in real time. A Shame, but there were some notable exceptions to the F3 QWI Training flight's efforts, but this again in my view, was down to the specific student's own personal skills and personality.
Other forces, like the Jag / GR / and Viff, had a fantastic ethos of learning and endorsement of ideas, which I so hope the Typhoon has adopted. I guess time will tell.
Having Said that, It's a new dawn, and certainly a QWI qual indicates that you have achieved a level of capability which may be useful, but only in service, or working outside directly with certain defence contractors.
Advo