This was the statement made in this article
http://stuff.co.nz/4648975a13.html
"Australian telecommunications analyst Paul Budde said introducing the WCDMA network should allow Telecom to halt the decline of its mobile market share but would not bring about significant growth. Once NZ Communications opened the country's third mobile network next year, it would probably take business from Telecom than Vodafone"
I personally believe that Telecom will arm wrestle Vodafone and with a superior coverage network and availablity of handsets and equipment it will be telecom that possibly will take a commanding lead, IF they build the network well and go hard at changing the perception of the company in the market place.
NZ Comms will do more damage to Vodafone initially i feel.