[inquisitor]

These Huawei 3G hotspots are probably the best stuff available, but you need to mind frequency bands. There are five relevant 3G frequency bands used in the world and most devices support only some of them.
While in the Americas (ITU region 2) 3G networks are operated at 850, 1900 and 1700/2100 MHz, the rest of the world (ITU region 1 and 3) use the 900 and 2100 MHz band for UMTS.
Australia and New Zealand belong to the few countries where frequency bands from the different ITU regions co-exist by Telstra using the 850 MHz and 2100 MHz band for their Next G network while Vodafone and Optus run their networks at 900 and 2100 MHz.

So if you seek full compatibility with all Australian operators your device should support UMTS at 850, 900 and 2100 MHz. The latter two are also used in Europe, Africa and Asia. But for the Americas you may also need support for UMTS at 1900 and at 1700/2100 MHz - depending on where you are and which network you want to use.
Afaik there's not mobile hotspot available supporting more than three frequency bands, so the E585u-82 is probably the best choice in your case.