AAnet used to be very good for a budget ISP. Unfortunately their service has degraded over time.
Be wary of the terms they offer on the contracts. There's no notifications if you approach or exceed your download limit - not even an invoice after the fact. You get charged for excess usage.
If your Credit card expires, they won't make the logical assumption that it will still be expired the next day, rather they'll attempt to bill you again. And the next day, and the next and the next and the next. Each time you get a fee for the failed attempt.
Customer support used to be OK.
My experience is that this winds up being more expensive than it looks.