I bought a Duck in 1983 after having flown a WW Raven and then a Harrier. I had been spoiled by the excellent light handling of my two previous gliders. I hated my Duck. It launched well and had a better glide than the Harrier but trying to core a thermal always felt like dancing with a fat lady. It had heavy bar pressure and slow roll response. It landed like a brick. I never whacked so much on landing as with this glider.
I have the 200. There were just six made I hear. I have towed it and it was a pig. I trike it usually and it does OK. The tips dig in during turns and is probaly spirally instable to some extent. I modified the sail to have a center zipper access. Mine is still flying occasionally.
I'm surprised at the previous comments-I flew a 155 and it was the lightest handling double surface glider I ever flew-scratching light inches from a cliff face was a pleasure. Unfortunately it also had the smallest flare window of any glider I ever flew, which, coupled with the fact that I hung as low as possible and had just started flying prone after years of supine (and yes, I have short arms) led to some sound whacks and a shoulder that bothers me to this day. I would have flown it a lot longer if I wasn't afraid to land it.
I learned on a duck a long time ago. Landing this kite was easy, as long as you had a smooth 10 mph headwind. Anything else, you better have wheels. I replaced the down tubes many times. I still have Two Ducks, one is for parts. I would love to donate them to a Air Museum. The Air Museum I wanted to contact in Charlotte NC had closed. Please let me know I if you have any information or suggestions. Thanks!