I've moved to Australia, and then back again to the UK, both times using a 40ft container.
Both times, I wished I had used the move as an excuse to slim down and take less stuff with me rather than ram it to the max! (I didn't!)
Not much use I know!
Its a difficult one, because we don't know what you have, were planning to take or leave! What I will say, is that almost everything costs a bit more in OZ (sometimes a little, sometimes a lot!), and setting up a new home is always an expensive activity, so if you already own something, bring it. Even if its crappy old stuff, it will get you by for a while whilst you find your feet. Beware of bringing stuff like gardening equipment, as it will be inspected with a fine tooth comb, can still bring it, but make sure it is really clean.
Note - timing your shipping if a fine art. Took about 9 weeks for our container to transit the globe and actually get to our new house in Melbourne (including 10 days in customs) Think how you will survive in that gap - you can choose to have your stuff go ahead of you so it arrives as you do, or fly out as your stuff leaves and spend the first 9 weeks of your new life waiting for your gear.