whos MBA is better Australian,US and UK?

It's the SCHOOL not the country.
In the US it's probably Harvard.

A U.S. education is still the envy of the world. However, it depends on where you will be working. Arguably, a U.S. MBA will land you jobs in all three of those countries. It will be harder to find a high paying executive job with an MBA from one of the other two countries outside of the U.S.

Well it depends person to person.One may not need an MBA if you can learn all these things while working,,,,its basically case study.Anyways,coming back to your point i think MBA from US is a better option as US universities are better funded,have good reputation all over the world.There are many US multinational companies working in the world and a US degree will make it easy for u to get into any of them.There are several good universities with good MBA programs, to name some they are British Columbia,Yale, Cornell,Stanford,Harvard.

Definitely, an MBA from UK is superior. UK has been educating people long before these other "countries" ever existed. But, do not get too caught up with which MBA school you want to go to. What you really know and how you can apply it in the real world is different than having MBA in paper. A lot of people made their mark in this world without any degree. The Wright brothers did not have aeronautical engineering degree but they were able to discover flight.

Even if you hate Bill Gates, he is an example of a person who got "it". You can have all the MBAs and PhDs in the world but if you don't have "it", you are just among the millions of unknown educated wannabes.

I disagree with the person who said the UK. It's the USA. MBAs from schools in the US - especially the top 25 MBA programs - hold huge cache outside the US.

In fact, working with some international MBA students, they've told me that it doesn't matter WHERE in the US you get your MBA, but that it is from a school in the US. I'm sure that depends on which country you're originally from, and where you plan to work. These students were from India, Saudi Arabia, Iraq, Albania, Russia, China and the UAE.

There are certain exceptions. An MBA from the top European programs - say, INSEAD or the London School of Economics, will also open doors.

US of course.
Even though the educational system in US is not as good as it could be (actually very poor in many cases), in MBAs there's hardly any* difference in what you will learn in one school or the other. Thus, what matters is reputation and your subsequent earning power.
Have a look here:
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of the first 15, 10 are from US.