I've flown 72 flights on PX and can recall 3 delays that resulted in missed connections. One was insignificant and I was reaccommodated with no net effect on my trip. The other two were more significant, one of which basically ruined a trip.
I did try to fly QF or VA where practical so if I'd used PX for those trips, my results might be slightly worse
There were a handful of times where it looked like PX was having a major SNAFU and I was glad to be booked on another carrier.
Hopefully that helps give you an idea of the odds
CNS is a pleasant enough option if you can get there efficiently. There are about 4 return flights at various times most days across PX and QF link so some good contingency and a very quiet (slightly weird) airport.