Ideally I would have gone out and purchased a usb from each of Telstra, Optus, Vodafone and 3 Mobile to complete the tests myself but maybe will have to wait for next year to do this. Instead I have been scouring the net to find a test that a reputable magazine has performed on mobile broadband speeds that will assist you the reader in making your next wireless broadband decision.
Let me tell you it isn’t easy. It continues to baffle me just how confusing this whole industry must be for the everyday consumer who hears all these words relating to internet speed, bandwidth, data, downloads and uploads, the list goes on.
I don’t envy your position at all. At the end of the day though, what can be said about mobile broadband is that if price is an issue for you and you can only afford prepaid internet, or if you are only browsing the web and doing limited downloading/uploading and if dialup or satellite are the only other options available to you then mobile broadband is a great alternative.
The table below will give you some idea on what maximum speeds you can expect with mobile broadband.

So until I can find the $500 to do the test myself I will refer to a report undertaken by APC Magazine in Oct 2008. So its not the most current and you can only assume that usb modems have improved over this time and that speeds may also have improved somewhat. What is good about the test is that it covered all times of internet use, from web browsing to watching videos.
It is by far the most comprehensive comparison I have found. So here are the results:
| Wireless Provider | Published Speeds |
Load smh.com.au | Load microsoft.com | Stream Video | Speedtest.net Download |
Speedtest.net Upload |
| Optus | 512kbps – 1.5Mbps | 22 sec | 31 sec | 449 kbps | 920 kbps | 329 kbps |
| Vodafone | 3G Broadband | 59 sec | 32 sec | 378 kbps | 317 kbps | 111 kbps |
| 3 Mobile | 3G Broadband | 26 sec | 20 sec | 454 kbps | 1628 kbps | 350 kbps |
| Telstra | 550kbps – 3Mbps | 10 sec | 17 sec | 1013 kbps | 3728 kbps | 522 kbps |
| Virgin | 512kbps – 1.5Mbps | 33 sec | 56 sec | 192 kbps | 636 kbps | 335 kbps |
Note that these tests were undertaken in CBD Sydney, so speeds outside of the CBD are likely to be slower and will gradually worsen the further you move out. They may also vary from city to city and probably by time of the day undertaken. You can view the original report here
In conclusion however, it seem that the fastest speeds are available by Telstra, second that being 3 Mobile, then Optus then its probably a tie between Vodafone and Virgin Mobile.