Filled with interviews and clips, the two-hour documentary is extremely well done and absolutely worth checking out by Trek fans.
What's particularly interesting about the documentary is that it is not only a look at how the captains themselves changed over the course of their individual series (or film in the case of Pine), but how the Star Trek franchise itself has changed. Each captain personifies the franchise at the moment he took command, and the behind the scenes tidbits about the making of the shows are intriguing. Also a lot of fun are a series of stats (most encounters of the closest kind, first contacts, leading of landing parties, etc.). It's reassuring to know that Captain Kirk, despite having the smallest number of episodes, fares very well in these polls.
Below is a trailer for the documentary issued by the network.