Only the basic edition is sold in Australia at the moment. Ordered one in early September and thats what was shipped.
The Australian power adaptor runs a 110-240v input, so power wise you should be fine. Hopefully the US version is variable power input also
It will not work with a prime account from Australia. All other apps like Netflix works fine. I got one from US and it is Geo blocked if you login using your amazon account here. But if you login using a US account it works just fine. Which I Think is very silly.
I have used one from US for 2 years and then in a firmware update Amazon removed the Prime App and the ability to access PrimeTV by using Silk. They have also blocked being able to download the Prime App again. Not happy to have functionality removed that was previously available.