To me the main difference is the lifetime membership of Gold (which gives me lifetime Qantas club). Also partner membership of Gold - which my wife has just received :-)

Foxpro, would be great if you could expand a little on the AA differences,particularly rewards. I prefer to fly Qantas metal - particularly Syd/JFK so that I avoid the AA ersatz First class.However it appears that if I qualify via the Plat challenge I can keep my QF choice AND get better miles.
BTW I think that QFF guys are looking at the problem with not getting bonus miles on non QF OW flights.