I would hazard a guess that there has been more PT6 in flight failures/shutdowns than the RR250 anyway.
The PT6 is under engineered, uses far to much fuel for the power produced making it IMO inefficient. The only advantage is the ability for maintenance to be performed on the hot section without having to remove the whole engine making it preferred by engineers over the likes of a Garrett. I don't care what a 'mechanic' likes to work on, I prefer something that is robust, reliable and offers efficiency.