It would be false logic to assume Australian medical schools are backups for people who did not get into the US or Canada. The fact that you got a 6 on a section will disqualify you from many schools in Australia. If you are set on practicing in North America, SGU is a good bet.
The advantages of Australian schools are that they are real research oriented medical schools, there is a chance to practice in Australia if you like it and many take this option, the quality of life in Australia is unbeatable, and I lived in many different parts of the world.