Been in the US on and off for the last 6 years and wouldn't head back to Aus if you paid me. Quality of life here is fantastic and as previously stated, your dollar goes so much further. Granted things like health care and education for the kids are things that need to be researched properly to get the best set up, however the size of the aviation industry, opportunity for growth and personal progression, network potential and just general living things like entertainment both in and outdoors are second to none. I've lived in California and now Nevada (Vegas to be exact) and life is bliss. Another thing to mentioned ... GA flying is incredible. Airstrips everywhere, most have full service FBO's, rental rates are ridiculously cheap etc.
If you have the opportunity to get over here, particularly if you are young and single, do not pass it up.