Works for most plans, even gigabit.
Obviously you cannot apply this code alongside other longer term codes like the "$x off per month for the first 6 months" ones if you're looking for a longer term relationship.
You'll also need proper hardware to take full advantage of gigabit. That's everything from the last mile NBN infrastructure leading to your house, the router (lower end ones that work fine for ADSL and lower tier NBN might choke when flooded with gigabit) and even your motherboard ethernet on your computer (older/lower end motherboards might only have 100mbps ethernet, so you'll need either an adapter or a new motherboard).
*A ‘new customer’ is defined as an individual who has not had an active broadband service with Aussie Broadband in the last six months or hasn’t been an authorised contact, residing at the same address as the primary contact,on an active broadband service with Aussie Broadband in the last six months.