I lived in Australia for 2 years in the early 90's - when there was no internet! So snail mail & v. expensive phonecalls made connecting back to UK difficult, and sometimes increased the sense of 'isolation'.
I lived in Parramatta - which I guess must now be the geographical centre of Sydney as there has been so much urban sprawl out to the West.....
To be blunt, it all depends on your ages/circumstances. I was single, 26, made lots of friends ..... some of whom promptly married Poms or Yanks then buggered off!
Those who were married were a bit 'Stepford' with lots of baking & taking said baking to friends BBQ's (where they would BBQ nasty sausages called 'Snags' but the rest of the meat was way superior and cheaper than anything you'd get here! I had fillet steak for the 1st month - early Atkins LOL!).
But back to the script - you have to make the effort to make friends with the locals to get off the 'tourist trails'. That was the best thing I ever did, 'cos then you really get to see Australia properly. And stop comparing prices to UK and live in the $ not the £.
You have to make the effort to see and do stuff - yes it's a massive country, but if you fly about (and ignore the sqealing about carbon prints) it'll open your mind. Save for 6 monthly trips like the Gt Eastern Pacific train from East 2 West for example.
The danger is not actually travelling once you start working....and because it's so far from A-B you need to really make the effort & have the money to fly to save time. Persuade friends to see you then plan said trips.
Working is just sooooo refreshing 'cos the ethic is that you work to live. You get/or used to get 10 paid sick days a year which you could take when you liked. So if you fancied a day on the beach instead then off you went!
Melbourne was far more cultural than Sydney which was over touristy - though Sydney was trying to get cultured when I was there 12 years ago (for a mates wedding!).
Bear in mind that Queensland is best visited in July - the start of their Winter. You can go in the sea safely (nasty blue ringed octopii & box jellyfish in March), and of course there are very nasty snakes/spiders. You need to be very hardy to actually live there. I have friends who live there and like anything, you do get used to it.
You can ski in Australia but the resorts/runs are small/short.
You are able to go to Venuatu/Easter/Cooke Islands/NZ/Fiji (though unfortunately a lot of the Aussies treat Fiji like Benidorm - & it's cheaper to go there than to stay in Aus!!
Canada reminded me of what England must have been like 50 yrs ago. I havent lived in Canada but have spent several weeks on hols (near Vancouver/BC - in Nelson, both summer and winter - -30 in Banff!).
Alcohol is frowned upon after one glass, and the speed limit is 60MPH - they have white van speed traps even as you drive through the Rockies and you're the only car on the road!
Also a bit Stepford/lots of baking. But pace of life slower than in Australia, which is speeding up.....plenty to see and do!
I personally would prefer Canada to live in than Australia 'cos the ski-ing is superb!
Good luck!