Personally if I was the op I would do what my Sister is planning and rent out the house in Oz, come over here and stop with relatives, get a feel for the place then make a decision.
That's a good idea and probably what I would do.
I think you need to come over here for a good few months and travel the place before you make a decision.
There are some bad areas and some really stunning areas to live in this country. I'd recommend the South West if you're looking for a less hectic more laid back life, it's got some really nice beaches, stunning countryside and some big towns/small cities so you can get pretty much everything you'd really need.
The South East is certainly more busy and expensive but it's easier to find jobs.