I live in Australia and moving to Canada now, so I can share these points very well (I think).
Canada:
1) Cheaper to live
2) More opportunities and more interesting things to do in Canada and also near USA
3) North America in general is a better place for Business Owners especially
4) Cheaper schools
5) Much cheaper food & electronics, clothing..etc
6) Housing price (Vancouver) is more or less same as Sydney (Australia); but Toronto & Montreal are much cheaper than Australia
7) Rental in generally is much cheaper in Canada (around 20% to 30% less)
8) Cars are much cheaper in North America
But the weather is a factor, Canada has longer winter time, although. hardly snow in Vancouver. Australia is freaking hot every year, summers can be as long as 6 months, and it is really hot, this has added to huge costs for utilities.
Australia
1) Job market "seems" to be better than North America now, but it can be a misperception, a lot of jobs do not even exist in Australia especially those relating to IT, Multimedia, Hi-Tech industries. For instance, if you are in network or telecommunications or semiconductors, then it will be hard to find job in Australia, so make sure your skills are relevant to Australiane economy.
2) Cost of living in Australia is a joke, it has been rising every year and is now catching up to Europe. Food is especially expensive here because of fewer competition, high petrol price.
3) Racism is not really an issue in Australia or Canada, back in 1980s and 1990s, it was a big problem. Although, I do not find Australians as "open-minded" as Canadians in terms of accepting other cultures in some rural areas and cities. Generally, it is OK.
4) Not a great place to be a business owner, but a better place to be an "Employee"
5) Do not be fooled that people are laid-back in Australia, living cost is high, so many people have 2 jobs or double-income families; you have to work hard either in Canada or Australia.
6) Utilities bills have skyrocketed over the past few years unfortunately.
7) Very far away from the rest of the world and not many cities to visit in Australia, travel & accomodation costs are very expensive compared to North America. It is close to Asia though if you like to visit Asia regularly (min. 7 hours flight).
I have lived here for over 20 years; the living cost is what has driven many people leaving for overseas, that said, Australia is growing, but at a cost of many benefits; family benefits are not as good as before, fundamentally, it is a small country (population wise), and this means higher cost of living.
Rental cost is very high here, it is normal to see rental A$500/week just for a 2-bedroom apartment in some not-so-good areas.
Interest rate here is also about 3 to 4% higher than Canada, and housing is actually more expensive.
Visit both countries first, go to realestate.com.au to get an idea for property market in Australia.
Both are great countries; I am more in favor of Canada as I like colder weather; and most of my businesses are outside Australia anyway.