Australia has always required a licence or log book endorsement for multis. For turbine equipment Oz requires a type rating with a formal ground school & then flight training. In the case of the MU2 Oz additionally requires ground training & certification for flight into known icing. The known icing requirement was introduced after an accident where the pilot was able to report the a/c's behaviour while falling out of the sky due ice accumulating on non-protected areas. Short answer is 'don't fly below the Vmin for icing'.
I did ground school with an 8000 hr MU2 time bloke. He had nothing but praise for the aircraft **subject to flying it in accordance with its peculiarities**.
He said the a/c's traps for the unwary included jet-like handling instead of the more familiar prop-like handling, spoiler-only roll control so using any roll input to manage asymmetric ops had adverse performance effects. He said the technique to use was to wind in up to full roll trim (the a/c uses dedicated small, inboard ailerons for roll trim) and a few other things related to the engines & fuel system.
Otherwise I was left with the impression of a capable aircraft that is somewhat similar in its 'traps' to other turboprops as the Aerostar is to other light piston twins. Respect it's peculiarites & get a lot of safe capability.
