Flutter is a big problem on all 3D planes unless you use a low pitch prop and keep the speed down. The large control surfaces are easy to flutter.

The 4D has a full flying elevator and rudder-no fixed surface. This will give you lots of control, but is also easy to flutter. Sort of, you don't get something for nothing. If you want to fly 3D planes, you will have to learn to use the left hand and keep it slow. Watch the 1/3 scale and larger acro planes. You won't see them flying fast.