What is the difference between USA and Australian Servers?
The USA servers provides more traffic allowance because the cost of traffic is lower in USA. However from an Australian point of view, due to its distance to USA, there is a slightly bigger latency for the data packets to reach it, so you may feel that the USA site is slightly slower than the Australian one. The difference isn't all that big though. Try comparing www.quadrahosting.com (in USA) and www.quadrahosting.com.au (in Australia).