Question abour reting cars in Australia

Tweet

Ok, I've traveled a lot but it's always been within the US. Does the whole car rental thing works the same way in Australia as it does here? I was looking around online ( http://www.121carhireaustralia.com/ ) but honestly I think I'd rather just do it in person. Can I just show up at the airport after my flight gets in and go to the car rental place and get one there? Are there age limits or any other things that they check in Australia that they don't bother checking in USA? Thanks!