I feel its one of the only pairs that reflects the actual worth of two currencies. Australia's house is in order. They've maintained it throughout the whole global "crisis." Have they been affected? Sure...but they've managed better than (arguably) anyone else. Hence...their currency has held value...and appreciated. They also haven't (grossly) manipulated or intervened either (aside from rate cuts).
You can't gauge anything against the Yen, because of massive interventions...AND they've been in recession for 30+ years, I believe! The Franc? No can do...massive manipulation (peg) and interventions. The Pound? Who cares? Sorry...but really. Done their QE's though, too. Again...plenty of manipulation. USD? Mass manipulation (QE whatever # it is now, Zirp...the Twist etc etc etc). The cause of a lot of the "crisis" and they continue to bailout Europe and probably help the Yen and Franc interventions, too. The Euro? Well...certainly having a rough go of it. Is rightfully depreciating. Where can it best be seen?
I feel EA seriously offers one of the "truest" state of affairs in that regard.