The Millford Sound was absolutely incredible, I very highly recommend going out to see it if you're in Queenstown. This specific tour was a really great way to experience it. The bus was brand new and had USB ports for each seat to charge phones, cameras, etc. Our driver had a nice dry sense of humor and was very knowledgable about the region. He pointed out a number of very beautiful points, backed up with interesting facts about each, and knew the answers to a number of questions posed by the guests.
The cruise was incredible in all aspects. The staff working the boat were really friendly and came to talk to each of us to tell us about the locations we were seeing. The driver of the boat took us exceptionally close to a number of interesting sites, including resting seals and a number of waterfalls.
Finally, our flight back was really cool. The bird's-eye view of the area wrapped things up perfectly. Our pilot was clearly very experienced - the area is exceedingly windy, so it's not the easiest flight, but our pilot was able to keep the plane as steady as can be.