I fly as a passenger regularly.
For what its worth, my opinion:
Tiger - Never used them.
Jetstar - Long check in usually, rarely have meals for purchase available, terrible seat pitch, pleasant enough crew and Qantas like baggage return (could be fast, could take 45 minutes).
QANTAS - I LOVE the automated check in / bag drop! The lounge is average, I usually don't bother (if I had to pay for it I wouldn't) and the on board meals are either a snack (yeah right or something to skip). Some of the cabins are really tatty now, particularly the seats on the 767 (although they are being refurbished). If you get one of the new 737 with the individual TV's, they are great! Baggage return is a lottery in that it can take 5 minutes or 45 minutes.
Virgin Blue / Australia - Check in is an area for improvement. Bag drop is just that. If you want to change your seat, then go to check in. Crew are OK but cabins range from tatty to bewildering (no in-flight entertainment at the moment - I understand it's coming), meals the same as Jetstar, but bag return usually very quick.
All travel for business so I don't pay.