I enjoyed both races:
NZ - the lake is amazing to swim in crystal clear water, if the wind is blowing it can get pretty wild on the lake, mass start which is not a problem as it's wide enough not to get beaten up. There is a long run to transition from swim exit.
PM:- I enjoyed the swim including the weir crossing which is something different, rolling start which I enjoy, gets very shallow in some sections
Winner - NZ
NZ - undulating for the first part out of town but then flat in the valley, road surface mainly country chip mix with not a lot of pot holes from memory, wind can get up on the second lap of the bike most often a head wind on the way back to town
PM - worst road surface I've raced on thus far, lots of pot holes and country mix in sections as well
Winner - NZ
NZ - challenging run course, it doesn't look like it from the profile but it's an undulating run with lots of twists & turns
PM - flat run with one hill, I found it easier than NZ
Winner - PM
For spectators you can't beat Port Mac especially on the run were they can see you multiple times per lap when running around the Caravan Park. Lots of support from locals at both races but I feel there is a better finish line atmosphere at PM, it was a lousy afternoon/evening in NZ when I did it so that would have reduced the number of people at the finish line.
You can't go wrong with either race.