If you haven't had a chance to read this Macleans piece this week, "Wake up and smell the kiwi," you should definitely check it out.
The author, Chris Selley, gives a good explanation on how New Zealand came to change its voting system and the voter reaction to the change.
Selley correctly points out that Mixed Member Proportional has made the New Zealand House of Representatives more diverse and reflective of the population, as claimed by fair voting proponents in Ontario.
Also, he notes that MMP has not been unstable, as stable and working coalitions have become the norm in New Zealand.
Finally, Raymond Miller, chair of the political science department at the University of Auckland, the leading school in that country, says this:
"I've got 300-plus students studying New Zealand politics, and I have to explain to them how the old system worked," he says. "I don't think they have any affection for it, and there's certainly no sense of nostalgia."