I'll throw my two cents in. Although I have not lived in other countries, I have traveled a few places abroad. The old saying, "it's a nice place to visit, but I wouldn't want to live there" rings pretty true - for me at least. Of all the places I have been, we really do have it pretty nice here in the USA (even though we do have our problems). Not to mention that I was always looked at as a foreigner; it just seems that you are never really a part of the "culture." I can't speak for Australia though, as I have never been there.
I guess my advice would be to see how your wife would handle being away from her family, as well as her family's thoughts on being away from yours. Make sure you think (and prayer wouldn't hurt either, if you are a "religious" man) long and hard about it, and get plenty of input from your wife before you make a final decision. Wahtever you decide to do, good luck and I hope that you and your wife can make the right choice.