I bought the Optus prepaid wireless broadband usb modem in 2008 because the unit I moved in to did not offer ADSL2.
In hindsight I wished I had never bought it. Reception and speed is dreadful in Wollongong, I rang technical services to complain and the Optus rep told me that there was only one tower in Wollongong and nothing was going to be done to improve the situation, insofar as adding more towers.
In practice, the connection is so bad, I frequently get timeouts trying to go to websites, and as for watching video, forget it!
I made a formal complaint through official channels to Optus, who never had the decency to reply.
All in all, $200 wasted. Even a dial up connection would have been faster and cheaper.