My wife and I just returned from a month's trip to Australia. We would recommend it highly to anyone who has thought of going. It exceeded our expectations.
It is a happy country, with a strong economy, low unemployment and fascinating scenery and flora/fauna. It is a surprisingly multi-cultural country as well, with many first/second generation immigrants yet little ethnic or cultural tensions. The Aussies are fun people, relaxed and they don't take themselves too seriously.
It is a long trip; took us 24 hours one way, and almost thirty hours the other due to a long wait between flights on the West Coast. We used Marriott Rewards points to upgrade to Business Class (converted them to United Airline Miles), and it was worth the expenditure.
We visted the cities (Melbourne, Adelaide, Hobart and Sydney), the Great Ocean Road drive between Melbourne and Adelaide, Kangaroo Island off the coast near Adelaide (wildlife viewing), the Barossa Valley wine country north of Adelaide, Tasmania if you enjoy getting outdoors and hiking, the Barrier Reef snorkeling/scuba diving, and the Blue Mts. a couple of hours from Sydney. We did not do the interior (Ularu/Ayer's Rock, Alice Springs) since it was very hot in their summer and full of flies (need to wear nets over your heads etc.), nor did we get up north near Cairns since it was their monsoon season at this time of year.
Sydney is as good as everything that has been written about it, a world-class city. Plan on at least four/five days there if you want to do it justice.
Next year we plan to do a similar trip to New Zealand; many have told us that if we liked Australia we will also enjoy NZ. We will use our Marriott Rewards points to upgrade to Business Class again.
By the way, it is best to upgrade to Business Class as far in advance as possible while they still have upgrade seats. Most airlines will not book seats more than 330 to 350 days in advance, but if you wait until three months before you go such upgrades may not be available.
So, go to Australia if you've ever given it any thought, and use your Rewards points to make it a comfortable flight.