I have been to Aus and New Zealand a couple of times, whichever airline you go to its one hell of a journey! if you can get a stopover for a couple of days, preferably both ways but definetly on the way back. The flight is a killer!
Favourite stopover for me was Hong Kong, also been on stop over to Singapore which was boring, Bangkok that was OK, Las Vegas hated it.
I've always gone for the cheaper flights, not used Malaysian but used Quatas, British Airways, Quatar,
What I've found is the not so known airlines have older planes but also more leg room and bigger seats.