Several different companies operate cruises on Milford Sound: Mitre Peak Cruises, Real Journeys, Red Boat Cruises and Southern Discoveries are more focused on conventional tourists while Go Orange and Jucy Cruize are cheaper with more of a budget backpacker focus. A lot of the conventional cruises are on big, impersonal boats but Mitre Peak Cruises have the smaller boats and offer a less touristy experience. Real Journeys also have some smaller boats.
The main advantage of these cruises is the view of Mitre Peak, so they are a waste of money when it is covered in fog and low-lying cloud. The first cruise departures each day are usually much cheaper, primarily because your view is more likely to be obscured by fog; although these can be great value on a clear morning.
The following video and booking calendar is for cruises on Mitre Peak Cruises: