Yeah, finally somone who really wants to fly
Apart form what USMCmech has already said Aviation Legislation would also be something you wouldn't have to redo.
When it gets to the handling, only horizontal flight with reasonable airspeed is quite similar to fixed wing. Any slower flying, turns, hovering, etc. needs one control input more. Needing you to controle three axis simultaneously. Hence it is slightly more demanding than fixed wing. Minimal inputs show maximum effect.
And engine failures/auto-rotations - whoa! Completely different technique to fixed wing, as the accident statistics prove with fixed wing pilots flying rotary winged aircraft.
True, unfortunately most pilots who have converted to helicopters have the instinct to push the stick forwards in case of an engine failure. To perform an autorotation though you need to turn the rotor into the "wind" and therefor push the stich back. In the worst case (say R22) you only have one or two seconds to react. Therefore always have an eye on your Rotor rpm and the torque.