There are a lot of similarities between Canada and Australia. They both have high taxes but more social services. Property in the major cities like Melbourne, Sydney, Vancouver and Toronto is very expensive. Not quite HK like but far too much for what you are getting. Both governments have taken measures to cool the property market by taxing foreign investors and implementing things like vacancy taxes. Both countries have received a lot of immigration so the main cities have lots of different cultures however it gets lily white in a hurry once you get out of the cities. In my opinion, you get better schooling in Hong Kong but there's more pressure for kids to perform academically and it's not cheap. Kids that are not high achievers academically will likely be happier in either Australia and Canada and there's better support for those needing help. Lifestyle in both countries is less centered around work and leisure pursuits are more important. From Canada, you have closer access to Europe, US and Latin America. From Australia, it's easier to go to Asia. Both countries have a big car culture and you can drive forever in many directions. The biggest difference is climate and cultural, winter is a big thing in Canada. If you don't like the cold, it's misery from October to April. Vancouver, Victoria are warmer but rainier in winter and high property prices. The East Coast is colder, snowier and somewhat cheaper. Popular sports are north american(american football, baseball, basketball and of course hockey). In my opinion, the weather is better in Australia and the culture is closer to the UK with rugby, cricket, OZ rules being the main sports. Great for watersports, golf, cycling etc... Can get wicked hot in the summer with days over 40C and you can still have a taste of winter in the Victorian Alps or if you go to NZ.
Best to at least take an extended holiday to get a feel for it. No one can advise you on how you will feel. If you grew up in a warm climate, you're likely to enjoy Australia more. After HK, you will feel like you are getting raped on taxes in both countries and if you have private health insurance, you're likely to find it a bit hard to go back to public hospitals. In Canada(like HK), you can wait for months and even years for elective surgery, scans etc... Of course, if you're willing to pay or you have private insurance then there are no issues.