I can speak a bit to AA. I fly to Australia a couple of times a year and use my AA status for the OW benefits. Honestly though, it's not the same as you would expect in the US. As another person posted, you won't get any upgrades. What it will help with are things like early boarding and lounge access (assuming you have status). TBH the early boarding isn't anything great as travel in AU is a breeze and overhead space isn't limited like it is here in the US. AA will likely require some sort of challenge so unless you have domestic travel it may be difficult. Granted if you fly over on AA metal a few times in a 90 day period you shouldn't have a problem getting status. What status do you have with United? Also worth noting that the miles earned on QF domestic flights towards AA aren't like they are in the US. There are no bonuses or anything with status, just straight miles.