The diesel is all very nice, but why does it have to be FADEC? Why did they make the damn thing so dependent on electrical power? to the point where there are batteries in the tail, so that when the inevitable electrical malfunction occurs, the engine won't quit (immediately anyway). How good are those batteries? what condition will they be a couple of years down the road when the alternator spits the belt off? are you willing to bet your life on them keeping the engine running until you can find a spot to put it down?
I know some guys flying one, and their engine has already quit once (It restarted though, at about 8000ft....just an electrical malfunction - what a surpprise
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The beauty of aero piston engines is that as long as you feed them fuel and oil they keep on running. these thing want fuel, oil, electrical power, and coolant.
I really can't see them making a huge mark in GA for quite a while yet (if ever). the margins are too small. The old 1970's technology can be maintained with a spanner, for these things you need a laptop and a cable (and someone who knows how to use them).