1. All of them will let you down at some point
2. Tiger will let you down more often and more severely
3. Choose from Qantas, Virgin and Jetstar
4. Book the cheapest and/or most convenient flights for your trip
5. Never be loyal to the one airline
Imo, service vs purchasing power remains yours with the above approach.
I now have silver with 2 airlines rather than gold with 1.
