I just had a car hire with Europcar ex AKL - it was cheaper than Hertz at around ~A$100/day (which seems about par for the course with NZ). I have Europcar Executive status and had booked the least expensive car (2 days, funeral) and at the desk got upgraded to latest VW with all the gimos and a few hundred k on the clock. Picked up, drove off, came back, dropped off, got the invoice as expected a week later, no dramas at all.
I have to say - I've used Europcar in AUS, UK, and NZ before with absolutely no probs. YMMV.