Our company operates MU-2s on medivacs.
Quick and cheap machines. Parts can be hard to come by, but they are dirt cheap in the states. Cheaper to buy a whole plane than the replacement part from Mitsibushi now.
Based in Canada, so icing isn't as bad as what is pictured in that link. That was a severe icing encounter while flying at night into unforecast weather. Was also the last plane in the fleet to have some modification installed that would have saved them a whole world of problems.
MU-2's have a bad rep as a doctor killer as they are as cheap as $250,000. Turbine hot rod can be appealing at those prices.
Have no idea about C441's.