Well, a question like that is kind of difficult to answer IMO, as the answer can be subjective in several different ways. Difficult based on the air frames performance...difficult based on individual piloting abilities...difficult depending on the field you desire to fly it at...etc
Do you see what I am trying to say?
Is the Rifle "difficult" for me to fly, as an Intermediate pilot with average eyesight and reflexes and a fairly large grassy field in which to land it in? No. Would the Rifle be difficult to fly if your eyesight or piloting abilities or choice of field is less than optimal? Definitely.
The air frame is honest as far as how it behaves in the air. It has not "surprised" me yet while flying it but it will require a good amount of concentration and focus while flying it and due to the speed, "things", either good or bad, will happen quickly.