kawoh, that's a great post! Interesting to read a bit more about RG's and MX's programmes. Couldn't agree with you more about NZ AirPoints, though if you fly in premium classes a lot it is not so bad.
The other factor to consider when choosing an FFP is whether you will be flying mostly with one airline or with a range of them. A disadvantage of UA when compared to AC is that the bonus miles you earn if you have status are only on UA metal, whereas AC's equivalent (threshold bonus mileage) applies to any status miles earned ie all Star carriers. For me, this outweighs the often slightly higher redemption levels on AC vs UA (though AC's 35K business class award from anywhere in Aus to anywhere in the South Pacific is a pretty impressive one!).
This recent thread might also be of interest regarding earning status:
http://www.flyertalk.com/forum/Forum82/HTML/001513.html