Another differentiator I have found in my experience is that the US companies also just seem to take the customer service side of things a bit more seriously than many local Aussie companies.
A few times I've ordered parts for cars or computers from local and O/S vendors on the same day and receive the O/S ordered items BEFORE the locally ordered ones. One time I received the O/S parts (Wheels From LA) in 5 days, which was just 1 day more than it took the local company to call me and say they didn't have the part I ordered from them and then they took another 4 days to send me a substitute part. that kind of thing doesn't help inspire people to do business with them in the future as the attitude is like "whatever", on top of the inflated price.
Cheers,
Snowy :)