I moved in October last year.
I had a job lined up with someone I used to work with in the UK.
I originally came on a working holiday visa, then had my 457 visa processed when I arrived (not the correct way of doing it), a lot of people seem to do it this way as it allows you to work for 6 months for a company, then if you like them/they like you, you can stay if they can sponsor you.
The sponsorship thing is a bit odd, some of it is very straightforwards, but then you can run into a "computer says no" scenario, depending on your occupation, you might have to title your job slightly differently to pass. Anything titled engineer requires a bachelor or masters engineering degree, but a technician role is fine.
I ran into trouble with my title being Engineer based without a formal qualification, I have a bachelor of science instead, but with 5+ years experience in the engineering field.
The first 3-4 months were tough, my girlfriend struggled to get work, but she has picked a job up now, not a career, but its a reasonable part time job with a friendly lot of girls and the extra income is great.
Things are going well now, we moved over here with FA as we were pretty skint in the UK, 6 months down the line, we're not really wanting for anything, bought all new things for the house, got a brand new car on order, our belongings from the UK are being shipped over.
Once you are earning here, things are similar cost % wise to the UK, but you will be earning more. At first you can go holy **** a bottle of coke costs the equivalent of 2 quid, but its swings and roundabouts, petrol is cheaper, food is about the same, electronics are cheaper, used cars are more expensive, new cars similar price wise.
I would never have bought a brand new car in the UK, would have been a full years salary, yet here its less than half my salary.
It's liberating in a sense that rather than having to penny pinch like mad and count everything up, having nothing left at the end of every month in the UK, being able to buy most things as/when we would like them and having money left.
You can earn mega money if you want to go work down t'pit, but if you have a family then its not very likely, wouldn't have much family time.
The benefit for me is working 5 minutes from home, shorter working hours and better working conditions. Socially its taken a while, but building up relationships now and getting out to do things, I play water polo (seasons over now) once a week and started road cycling.
EDIT: I live out in the country, I wouldn't move to Sydney, too much like London, just hotter imo.
And shipping times for bike parts, about 2 working weeks from the UK