You can upgrade ($99 charge applies) to the Mighty if you re-contract to eligible home broadband plans. If you do, you have to return the first or second generation set-top box you currently have to Optus. You can also upgrade without recontracting by paying a $99 fee.
Which now that I read it makes no sense. Its either a $99 fee or a contract or both or neither. Typical Optus confusing fine print.