Point of fact - Kiwis eat both Vegemite and Marmite, and the preference is binary and very strong (no-one likes both equally, that I've ever met) and survives the usual jingoism between Aussies and Kiwis.

I am a Kiwi, and like my mother I've a strong preference for Vegemite, though my father and brother are both Marmite people.

My wife is American, and has converted to being a Vegemite-lover after finally experiencing it correctly (NOT a mouthful on a spoon, like all those "look how disgusting Vegemite is" videos show). We did a blind taste test last time we were in New Zealand, and to my surprise we could both correctly tell Vegemite from Marmite, and both preferred Vegemite - even though it's Australian!

Edit: grammar

I like both equally, so you've now "met" one person! I was born and spent my first 8 years in NZ, then moved to Australia.

Freak. Everyone knows that Vegemite is the one true spread. Fun thing you can do with vegemite - get a bunch of French people in a room that have tried vegemite and get them to discuss whether the word is masculine or feminine. Some want feminine because of the 'ite' ending, others want masculine because of the nature of the product :)

I'm convinced Vegemite is something Australians thought up for the sole purpose of annoying British people when they buy it by mistake ;)

Both sounds like derivatives of thermite, so the confusion is at least somewhat justified :)