Seen one fly quite a few times. Tended to rock a fair bit in harriers, and then all of a sudden it would stall an fall off to the side quickly. Not very useful when you are low. Knife edge sucked on the one I saw, lots of coupling. The CG may have not been back far enough but it still seemed excessive. The quality of the covering and construction were very good, however I agree with the previous post about the sheer bracing. Not sure it would really hold that well after a bit of time on the airframe.
I think the worst thing about it was the colour scheme, made it very hard to see the orientation when it was away from you a bit. Didn't matter what the day was like whether it was sunny, cloudy, or in between it was just shocking to see at times