I'm planning on getting a SIM card for my smartphone while visiting NZ for a Contiki trip, with internet access being my only concern.
Wikivoyage mentions that Vodafone has a traveller SIM. The price is fine. The only worry I have is the quality of its coverage. In Australia, its reputation for service quality was bad enough that it got called "Vodafail". It might have improved recently though.
What is Vodafone's mobile data quality like, in terms of the amount of coverage, and the quality of coverage in those areas? I'll be staying on the North Island, and will be going between Auckland, Paihia, Waitomo, and Rotorua.