All the videos I've seen of their site show zero deviation from origin. i.e. the flyer always knows where it came from and can remember what zero pitch, zero roll and zero yaw where since the time it powered up.
I wonder how it handles going in circles around the operator. It'd then need to know where the operator was to keep the forward stick control always moving away from the operator. Otherwise all control inputs are in relation to the starting position and would get quite confusing when the model goes behind you without any other orientation. In helicopters, you have that big tail out the back to give you orientation.
FMS models only understand what control inputs are in relation to their current position in space so there's no way it could model the Draganflyer correctly without simulating gyros.
I like the one with the vertical stabilizer. You can hover it around, land up and down, land like a helicopter or fly it a bit like an airplane. Without the fin, it usually gets to spinning around so much that I lose directional control and crash. Once I had it spinning so fast it hosed FMS.
-- ggunners