Yeah .. what class of travel and how often do you travel ... ?
UA - you cannot get status unless you fly at least a few flights with them per year. Correct me if I am wrong though.
My folks pretty much do trips to HKG and Canada. Not Ozzie. I guess from *G you would be flying business class right. I'm not the best to ask then.
B/c you travel to TT, I think Qantas can be a good one. At least getting points and using them is easier than ANZ even for economy. If you keep it active, even for the basic member the points don't expire.
I imagine with a few other FFPs, at least the one I am with, ANZ doesn't provide points unless you are doing TT in business class. If you do that 3-4hr flight in economy you might not get points.
CX (Asia Miles) has a 3yr expiry. Not sure if that is extended or waived if you have higher status. Status requires a $50USD app. fee to join Marco Polo Club.
I don't know what the deal is with ANZ. To me it's only the 1 or 2 compl upgrade vouchers. To me it's just earning points and redeeming points. But earning any points is so hard with ANZ. I guess with the restrictions they placed on some other FFPs, esp if you travel to TT or the Islands sticking with ANZ (or forced to), might be something some people just put up with.