Through 4 season of Australia, their All-Star season is next.
Australia is just so different from US because of the fact that it's over 50 days and 24 players. It's SO hard for players who make themselves targets by playing a big game to last almost 8 weeks versus 5 weeks. Some of their winners wouldn't have won in the US, but very few of the US winners would have won Australia. The one negative is that because it's so long, some of the endings didn't match the greatness of when it gets from 20 players or so to about 5 or 6 players left.
Season 4 was the best of the 4, HUGE personalities and massive game play. The Australia franchise also has the most popular player in any series by a large amount, I don't think there is a precedence in the US.