A few years back I saw an article written by a fellow who was moving to aus for a few years from the US and wanted to bring his Bonanza out here. He costed both the ferry, and the shipping and found them both around the same price. He chose the shipping option, as he decided that that was a good opportunity to get a really good inspection done on the airframe while it was disassembled.
Personally, I'd do the ferry thing. A once in a lifetime trip.
Bevan..