The Sala case is not a reflection on N reg aircraft in the UK but the pilot flying a flight for which he wasn't qualified. If the aircraft was G reg or F reg it wouldn't have changed the fact that the pilot was flying beyond his ability and training.
I fly an N reg privately and it is maintained to the FAA rules and is perfectly legal. I fly VFR only on my CAA ATPL / SEP rating. There are several N reg aircraft at my club and everything is above board.
Do you have any figures to suggest N reg aircraft within the UK are more dangerous or likely to have an accident than G reg aircraft?