I have a Magic Extra 300 with an OS 50sx. I only have one flight on it and it seems to fly well. The control surfaces are massive, so big in fact that I am using high-torques on both ailerons and on the rudder. High rate rolls are on the order of 2-3 per second. I don't have the sense that vertical is unlimited with the 50, but it could be that it is not broken fully yet. Overall I am very satisfied with its aerobatic ability, however it snap-rolls strange... I'm not sure if its a setup problem with the 7U or the plane its self. I am anxious to learn how to do 3d with it.