Regs: the old "National Bank Cash Back" visa used to be the best for people who spent < $30K per annum. Not sure if the ANZ version works as well. After that, the kiwibank "no fee" mastercard was best (no rewards points, but also no fees)
As far as I can tell everything has remained the same since NBNZ became ANZ. I believe it's still the best value for my situation (<$30k annual spend + a joint card for my wife), plus what other reward is more useful than cash!