There's the usual tourist spiel, but you're asking about actually living here. Much the same as in America I imagine. Culturally very similar like Canada is.
That's really not true.
I'm 30 years old. I've lived in Australia for over 6 years, and was born and raised in Canada. I have lived NSW, and now live in Victoria (Melbourne). Regardless of the clear differences between Sydney and Melbourne, neither Sydney-siders or Melburnians are similar to Canadians. I can say the same thing regarding most of the country.
SIMILARITIES:
- Sense of humour
- liberal-thinking people within the middle-sized and large cities
- Nice, friendly people.
DIFFERENCES: Australians are, in general, louder than Canadians. They talk loud, and are rarely as courteous as Canadians. Many people think drinking is an excuse to act loud, obnoxious, and violent. Most people will say that they know alcohol is no excuse to act like an animal, but at times, it seems that the end result doesn't match the rhetoric.

Expect a surprising amount of public drinking, shouting at each other in public with little (or no) regard for others, and a bit of violence on most weekends and nights out.
Canada isn't perfect, but there's definitely less of this going on in Toronto then there is in Melbourne, despite Melbourne's city centre being around 10x smaller (I'm excluding all the business areas where nobody drinks or hangs out). Sydney is worse than Melbourne in this regard, but it's pretty similar anyway.
Australians also get a lot more violent at night after drinking, and I don't think you'd feel as safe as you do in Toronto, Montreal, or even Vancouver. Even Melbourne, which is definitely the "culture capital" of Australia and filled with annoying hipsters and yuppies, has a violence and racism problem. Funny thing is that Melbourne is less racist than the rest of Australia, IMO.
Don't get me wrong though. I like Australia, and I have loved every city I have lived in. However, before I ever moved to Australia, I have heard about the racism. I heard this from fellow Canadians who are white (I'm Chinese-Canadian), I heard this from an Irish friend, from people in London, Hong Kong, and from my close friend in Toronto who moved to Australia for 6 months. He is of Indian background, but really doesn't act like it. Before he came over, we talked, and I was surprised when he asked me about it.
If you're white, then you're safe. If you're not white, then you're still safe, but not as safe. I never had any issues with race in Canada over 24 years, and I've had a number over the past 6 years.
THE CITIES:
I've been all over Australia (except the Northern Territories), and personally, Melbourne is fantastic.
I love
Melbourne, but there are so many people who "act" arty and dress in skinny jeans or whatever the most current fad happens to be, and I find very little that is genuine about most people who live near the city centre. My workplace is full of really nice people though, but that's because it's in between the city and the suburbs.

Having said that, the people who truly
are talented are a real treat.
The weather in Melbourne is horrid. It rains all the time, and when it's not raining, it's cloudy and about to rain soon.

It has a genuine winter where the temperatures drop to around 0-5C at night (like now) and 10-15C during the day. There's also no good beach nearby. Seriously.
The best thing about
Sydney is that the people are more typically Australian than those in Melbourne. Most Sydney-siders are not pretending to be something they're not, which is true for most Australians living in Brisbane, Perth, etc. Sydney is a bit more brash than people in Melbourne, and while that sounds bad, it's actually kind of nice when you've been in Melbourne for awhile. Sydney is huge, and only the city centre is nice. Western Sydney is like the worst parts of Vancouver's downtown core, except it makes up around 30% of the city. In other words, there's a lot of crappy places to live in Sydney if you don't have money. The weather is FAR better than Melbourne, and there's beaches all up and down the coast.
Both Melbourne and Sydney are too expensive.

Actually, all of Australia is very expensive to live in. Everything costs 0 - 50% more than it does in Canada. Forget buying books, CDs, DVDs, coffee, a bike, clothes, etc. Do it when you're on vacation elsewhere.
Brisbane is a nice middle-ground. I haven't lived there, but it's trying to become a bit more like Melbourne in a way, and yet it's very modern and not particularly grungy or anything. The weather is far better than Sydney or Melbourne, and both the Gold Coast and Sunshine coast are about an hour away.

North Queensland is nice to visit, but I wouldn't live there.
Perth is too expensive, although the coast between Perth and Broome is probably the most beautiful part of Australia. Same with Tasmania (all of it).
Tasmania is absolutely gorgeous if you love mountains, forests, and the outdoors. However, if you were to go to Tasmania, you may as well just move to BC or Alberta. It's a bit warmer, but that doesn't make it worth moving there rather than BC or Alberta.
Like in any city you live in, you'll become friends with the people you like, and you're allowed to avoid the people you don't like. In that way, you probably won't have many problems with idiots if you're not hanging out with those people. However, the issues I mentioned will still affect you by being brought up in the news and such.