I initially leaned towards non-stop but given the times quoted by Dave I'd go Emirates. I general fly Economy and while I'll pay a small premium for EK and try shuffle and scavenge to make flying EK Work (My alternative usually being ET with longer flight times and no benefits due to lack of status).

However all things equal 230$ even for 3hrs longer translates to over 70$ an hour. In South Africa as an IT professional I can barely charge that (sadly software developers and associated project management in SA generally charge in the 35-60$ range/hr). The question whether you collect miles or status also factors in then, I'd say the savings swings it slightly towards EK, also if you look at the savings as a percentage of the overall Qantas ticket cost it's not insignificant. People jump through hoops for 10% off on a flight on here.