My girlfriend and I were unsure about spending the kind of money involved but having been on the trip can confidently say there are few better ways to spend the money. If you've gone all the way to Queenstown then you might as well go the extra mile!
The flight out was in a high wing aircraft with 8 seats total (from memory) so although the flight out was relatively stately, the commentary from the pilot (Hayden, I think) was most informative - he filled us in on the LOTR sites as we asked for beforehand. After we landed (smoothly!) he helped us find the boat and got our tickets for us so there was no ambiguity about where we should be and when.
The cruise was good too, again with commentary from the driver. I don't want to give anything away, but be wary of getting your camera wet... I got a bit taken by surprise, my camera is weather-sealed but many aren't!
So, after the close-ups from the boat we got our flight back with Ray (I can see from the other review that his skills are very popular!). This aircraft was much smaller (um 4 or 6 seats, I forget, there were only 4 of us in the plane though) and it was low-winged which I think meant Ray was able to bank it nice and steeply for great glacier views. He was very diligent in making sure his three passengers were happy with the maneuvers he was making and he was talking us through everything right up to when we went back in to controlled airspace.
Transfers to and from our hotel (Rydges) topped things off nicely. Also the first date we booked was cancelled but re-booking was trouble-free and the arrangements were clear at all times.
What a great afternoon we had! Highly recommended.