Manuka has good characteristics and is a reasonable antibacterial. It seems to be possible to fake Manuka content with Eucalyptus, which is a shame however.
http://en.m.wikipedia.org/wiki/Mānuka_honey
Oh I'm not saying manuka isn't as exceptional as it's supposed to be, I'm just saying it does get special import treatment which likely drives prices up in NZ since more of the production goes out to non-NZ consumers.
That's more than likely, and there's probably an international manuka craze on top of it: my (euro) grocery has a bunch of the usual blended "flower honey" and manuka, and that's it. Manuka is the first monofloral honey I've found outside of specialized or semi-specialized shops[0] (which is a shame).
[0] well not exactly, (false) Acacia is a fairly common one as well due to its physical characteristics: it's very clear and stays liquid for a very long time so it's an easy sell. But it's even blander and nondescript than blended