They are both great slams, each with their own character and history.
The prestige thing is generally attributed to Wimbledon because it is as close to universally recognized a term, as the Kentucky Derby, Tour de France, Super Bowl, World Cup, etc. From true tennis fans to the less indoctrinated, people the world over know "Wimbledon".
On the other hand, since the AO moved to hardcourts it probably has had the better draws, year in and year out, in that few players choose to skip it because of its speed, like some players still continue to pass on Wimbledon.
The weather. While weather can be stifling during the AO it is obviously dryer than Wimbledon.
Night tennis at the AO and USO provide a totally different atmosphere and experience. I truly enjoy watching matches played at night. But I also like that W and the RG don't play under the lights.
And from my experience, the Aussies know how to have a good time.
All of the slams are unique. Each has its own distinct character. I do wish they would have left the surface at Wimbledon the way it was 2000 and prior for the stark contrast it provided to the French but its still unique.
I truly enjoy all of the majors.