There were many reports and speed tests of Iphone using the Vodafone network several months ago and initial problems with low speeds almopst of x2 dial up speeds. Seemingly speeds stuck at around 116 kbps.
Tonight i am at work-Waikato Hospital and I am getting speeds tonight of 1.825 mbps download and 336 upload. This is definitely the fastest ive experienced on their network so far.
Fastest before was over by the Hamilton Railway station at around 1.7 Mbps.
Near my home Near Te Rapa/Pukete I was maxing out 500-600 kbps I will test this again tomorrow morning. So looks like there recent tweaking has been paying dividents-at least for here in hamilton