I actually prefer Airlines that run Airbus as the economy seats feel more roomy than the 737. Qantas 737 has 17.2in width and 30in pitch, where as Jetstar has 17.9in width and 29.2in pitch, the fact that the premium carrier has a narrower seat backs up you claim there is no difference. I find the 737 economy seats extremely uncomfortable which is of course just an opinion, have always found Virgin and Air NZ service very good but only marginally better than Qantas and Jetstar. Check in experiences very similar…… overall I would just buy the cheapest ticket as none of the local airlines have any massive point of difference.