We have been on one previous PG cruise. We had the late arriving flight, 9:40 PM. We went from the airport to the bus awaiting us then on to the ship to check in. It was no issue; we were just happy to be there. For peace of mind, they have so many passengers on those flights, they will hold the ship if the flight arrives late.
That said, we are going to arrive a few days early this time just because we can. We couldn't have extra days off when we were still working. If you can arrive early, why not? It would be a lovely bonus.