I've done an AKL-LAX-LHR and an AKL-LAX-AKL in the last couple of months and AKL-LAX-AKL at least once a year for the 2 years prior, and found them to be patchy, at best. Some of them call prior to the flight and are absolutely fantastic about sorting any issues (usually our nut allergic kid) - one even putting us in touch with the kitchen directly to discuss special meals etc. Other times, no phone call at all, and when they do call, no follow up, not following through on what they say they'll do etc.
When they're good they're very, very good. When they're bad they're...pointless. It might help for NZ to do a better job of explaining to us what it is that they're there to do? My understanding from a lengthy talk with one at our hotel at LAX last month is that they actually have quite a significant behind the scenes management role, esp in any disruption etc. They hold an NZ credit card, escort pax to hospitals etc if they need to go. I guess all we see is the 'nice to have' service (or not) aspects. Be nice if there was some consistency.