Air New Zealand Air Points - KrisFlyer or Airpoints

Hi,

I have Krisflyer Gold Eliter card as I used to travel very frequently on SQ. Now that I am based in NZ, i was wondering should i change to Airpoints.

I would travel about 4 times a year on Business class either to the US or to Europe. I will be on business class seats for all my trips.

Any comments will be appreciated as I am flying to LA on Air NZ, and then AA to Miami, all on business class.

thanks in advance