ACORD - I am/was in exactly your situation. An AC SE from Toronto, who has moved to Australia - also AA Plat (comped). I've earned SE for 2002 and AA has now extended Plat for 2002. Like you, I have several overseas paid J flight per year.

I decided to switch to Qantas accumulation for several reasons.

1. I plan to be in Oz for a long time (maybe for good).
2. Upgrades. Being AA plat doesn't do anything for you on Qantas. However, you can earn and use upgrades in the Qantas program no matter what level of FF you are.
3. Any travel within Australia will be on oneworld, unless Ansett can rise from the grave.
4. Hotel point accumulation in australia is very attractive with Qantas (5/$1 AUD)
5. Aussie dollar credit card. (anz qantas telstra Visa, amex rewards, etc.) - i.e., if you're here long enough you'll want a credit card and you can earn qantas points.

Note: Qantas will NOT comp you. I barked up that tree for a while and gave up. Initially lounge access was an issue for me, until my employer bought Qantas club. But, I had them put the QFF number on my itinerary, then quickly flahsed my AA platinum card when I went in - no one ever bothered checking. Obviously if you're flying paid J not an issue, but if you aren't, then it is an issue.

If you move down, drop me a line - always happy to hoist a few with a fellow canuck.