I have purchased a few computers (3-4, both as parts and pre-assembled) through this company over the years, have never had any issues. The one time that an item was out of stock, they let me know the day after my order and I cancelled that item and they refunded that part of the order including the shipping component.
Have had one returned power supply that died, they gave me an RA number and an address to send it to. a few weeks later I had a brand new one sent through. Shipping to Cairns/Darwin was all within a week in my experience, usually only 2 days, which is great for up the Northern end of Aus. Prices are all quite decent too from what Ive found.
Only negative and the reason for 4.5 stars is the payment options available, all but the direct deposit cost a % to use. Have used the Direct Deposit method and due to the money transfer delay it took another 2 days over what it would have otherwise.