Depends on whether you want an interactive pet...go with beardie (vitti)...or something that you can appreciate without handling..water dragon.
Water dragons are brilliant in terms of an outdoor set-up that you can just watch. Be aware that outdoor housing for these is a must if they are to breed, and also if you want to see their 'true' behaviour.
Water dragons should be raised indoors until they are around 45cm total length, at which point they can be housed outdoors. Adult animals will easily winter in NZ conditions without any supplemental heat. You can also heavily plant out their enclosure as they will not ravage your plants...beardies will. Water dragons tend to be skittish from a young age, but once they are around 20cm total length they will start going for your fingers at feeding time..this seems to be when they start to gain confidence. They will also happily feed on butch white label dog food.
All this means that a group of w.d's is in the long run easier to keep than a group of beardies and cheaper too.
Beardies (vitti) on the other hand are tame from when they are very young. Ideally they should also have an outdoor setup for the summer months.
Coastal Beardies (barba) can be kept outdoors all year round from adult and are between w.d's and beardies (vitti) in terms of tameness and can be handled relatively easily. They will also quite happily share an enclosure with the water dragons as they are tolernat to humidity, whereas the inland beardie (vitti) is not.
I will have all 3 types available come mid feb. PM me.