My wife and I spent 3 weeks traveling the beautiful Islands.
We rented a Britz 6 berth Motorhome and we had nothing but great service from Britz. The vehicle was well equipped and did everything we wanted to do. We found NZ to be a stunning place with the South and North Island being completely different in things to do and see. We loved it that much that we are going back next year to do the areas we missed due to the poor weather....you really have to pick your times. We really enjoyed areas such as Kiakora and the drive to the gorgeous Napier....to be honest we enjoyed everything about the fab country....and the people were awesome. Rotorua wow wow wow....
The only thing I would suggest is do your homework about places to see and things to do....use information centres to find out what is free and what is worth while....a few things we did were overrated....also the roadworks were a nightmare.
Love NZ.....its Choice !!!