One of my buddies had one of the GP Flatana's. That thing was a twitchy peice of junk and did not fly anything like I see in that video. I'll be interested to see what you think of the real thing and how it compares to the AFPD version once you get a chance to fly it in real life STLPilot.
I've not had the chance to fly any of the GP flatout biplanes though so it might fly like much better than I've seen. The extra wing might make it a lot more stable than that flatana was. I can tell ya one thing though. If you fly a real flat-out like you do in the video you'll be fixing stress cracks after your first flight

My buddy put the flatana through very mild 3d and after 2 flights there were serious stress cracks in the foam. It just feels so brittle and that landing gear setup is a joke. I recommend leaving the gear off and harrier land it.
I was not impressed with it at all. He went through 2 kits. He was flying on the upgraded Rimfire motor with the recommend lipos and speed controller.