I've been on K2 Obsethed 189's for the past two NZ season and would recommend them to anyone looking for a ski that will take them through all conditions. I got them before heading to Hokkaido over the last northern winter (traded in from Armada ARV) and they truely came into their own there. While they are ideally suited to the soft stuff (love the McConkey turns) they still retain a sidecut and minimal camber to take you through crud and packed stuff. Nice and soft in the tail (although not as much as the hell bent) make landing sweet and I had no trouble landing or riding switch in pow, even at +3.
I have to say that coming back to nz I'm thinking about finding a ski with more stiffness and dropping the rocker to handle the harder pack here, especially up high and early in the season. I'm a weekend warrior now so my exposure to good conditions has dropped. I find the Seth pops in the nose a bit when trying to carve aggressively in hard pack, I'd rather have my tips engaged.
At the end of the day I would recommend you pick up a ski for soft (rocker, width, soft, less sidecut) and hard snow (no rocker, stiff, generous sidecut, wide tip-tail but narrower under foot), this will give you a platform to progress in any condition and you will enjoy it more. However with the cost of ski's I know this isn't always an option, so I would first try and land on the harder side for NZ conditions and pick up a pow ski when you can (or plan a trip to the northern hemi).
I've heard great things about the Gotama, but haven't ridden them. I'm a firm believer in the Volkl construction method and the stiff, even flex profile of their top line performers is great, look for something with some metal in it for NZ conditions (I would lean volkl way for my 2nd pair of skis). My mates who ride the Ant love it, but they are at it every day and riding the fresh whenever it falls. They also ride smaller, stiffer skis on crap days (4FRNT MSP, K2 Extreme etc) You could look at the Armada JJ as the elf-toe tech would suit someone looking for a carver that will float (and not dive) in pow.
You could always keep it kiwi and go the Kingswood Archetype, this will give the performance in all conditions (sublime construction with premium materials), although it relies on width rather than rocker to keep you floating.
Hope that helps?