The Australian is much worse, for me - the day session going on right through the night.
I don't mind missing the occasional night session at the US Open and I can get by.
The aussie is hideous, if you sleep all night you miss an absolute ton of action.
What's worst about it is that the majority of the action with good early round contests takes place during the night for the first week, then all the big matches are the night sessions in the second week so you have to make a very quick adjustment.
But still, as Aussie posters would understandably reply regarding the rest of the year, "Welcome to our world", so I won't complain.