My choice would have to be : Notars Because the designmeisters of Mesa; have removed the rear drive train.
With its length of service, the conventional tail rotor and attached mechanics: has had its proportionate incidences of failure.
Notars like all else,are in a constant state of development.
Thus improvements will happen.
Perhaps at this junction,we should invite the maintainance engineers to add to the debate.BECAUSE THEY ARE EQUALLY IMPORTANT IN LOOP AS THE PILOTS AND DESIGNERS.