I've written elsewhere about experiencing the beauty of New Zealand's Matukituki valley by car. Another great way to enjoy this spectacular valley near Wanaka is a jet boat trip with Wanaka River Journeys.
This company is a small and personal husband and wife operation which takes small groups up the Matukituki River and back, with a walk or refreshment break at the furthest point. Brent, the host on my trip, drives the boat expertly at high speed in impossibly shallow water, and is a wealth of information about the area. Not just tour guide trivia either - he is a maori whose ancestors have lived in the area for centuries, so he conveys real passion for the area as well as his extensive local experiences.
The trip provides the exhilaration you'd expect from a jet boat ride in New Zealand, but also allows time to take in the tranquillity and wilderness values of an undeveloped valley that is well worth visiting.
Since I did my trip with them, Wanaka River Journeys has expanded to include an optional guided forest walk on their regular journeys, plus jet boat trips which incorporate a helicopter flight to the Aspiring Glacier or a hike to the Rob Roy Glacier (as if I needed any more temptation to return to Wanaka). Jet boat trips in New Zealand aren't cheap, but when comparing "bang per buck" I think the trip up the Matukituki River still compares very well with the Queenstown alternatives.
If the thrill of the jet boat ride itself is all you're after, then the Shotover Jet at Queenstown can be hard to beat for heart-stopping speed in a narrow gorge (although the one at Hanmer Springs comes close). But if you want your boat ride to include fantastic scenery, a wilderness experience, history and culture plus great people, then I can recommend Wanaka River Journeys.
Wanaka River Journeys