It depends on your cabin. I have never flown Emirates before but tried the other 2.
If you want to fly in Business, I would recommend SQ, but make sure you are in their A380 (just book through their website, the equipment are stated there) and you will also be able to book your food via “book the cook”! they have fantastic menu!!
But if you fly Economy, take Qantas, the seat is better than SQ and they have self service bar, but the service is not as good as SQ though.
if you choose to fly First, SQ will be very pricey about £1500 more than QF since it will be in Suites and you will not be able to book it online. If you book online, one of the leg in both of your journey will have to be in Business ex: LHR-SIN (R), SIN-SYD (J), SYD-SIN (J), SIN-LHR (R). Which i don’t think you want, so, the other options left are QF and EK.
but again according to my friend
who flew on EK Suites, he told me almost everything were not working, the electrical door jammed and the ICE (EK’s AVOD) froze in which according to their FAs happen 95% so, unless you willing to pay more to fly with SQ, i recommend QF 🙂