I had never been here until the day I stepped off the plane as a resident! I have absolutely no regrets as I think that the opportunities offered here to us and our family outweigh the negatives - but I won't lie to you, it's really hard some times!
It is 'only' a 24 hour flight, but that 24 hours are a nightmare, squashed into tiny airline seats with bored, over tired children. I swore I was never making the trip again when I got off in Sydney.
You will miss the family support - we have relatives over here (cousins and an uncle) and it broke my heart when I saw them cuddling up to their grandparents and I realised that my children had lost that.
Social media makes it easier to keep in touch, but it also shows you what you are missing and that can be quite hard - Skype isn't a substitute for a gossip and a cuppa.
You will find yourself feeling tearful in the supermarket when you hunt in the international isle for the things you miss.
Australia is enormous!! If you're not living in a big city you might find that it's a long journey for decent shopping and if you are living in a big city then you will pay the price for it.
Life here is expensive, credit is pretty hard to get - you have to prove that you can afford it. We found it pretty hard to buy a car on finance before we'd been here for 6 months and ended up spending $13000 on a 10 year old shed (as cars are expensive here) as we had to pay cash. Wages are higher but so is the cost of general living.
Education is not free, even if you qualify as a resident and don't pay for schooling you are still expected to provide everything your child needs in the classroom right down to glue sticks, the school will provide you with a book list at the end of each school list for the following year.
If you qualify for medicare (depends on your visa), then visits to places like the ER are free but you will have to pay a co payment to your GP unless you can find one who bulk bills. You have to pay for all prescriptions.
There are no long evenings (well not where we are) even in summer it's dark and the mosquitos are biting buy 8.30PM.
People are friendly! I can strike up conversation anywhere (and I'm usually quite shy!)
Don't expect to suddenly become an outdoors person and move 'for the outdoors life style', if you're a couch potato in the UK that won't automatically change as you pass through immigration!
Not every Australian home has a pool, there isn't a spider/snake hiding behind every corner to kill you and some nights it too bloody hot to sleep 