If I were to answer the "title" question, then I would say aerobatics are very smooth controlled aerobatic flight. Like stall turns (hammer heads), large hurricanes, and pretty much precision flight like IMAC with planes. 3D is more "Smack". Take the heli and beat the ever loving hell out of it, but in a controlled manner.
As for the "post" question... Alan all the way. The other guy is just to pompous IMO.