I watched this earlier (backed on Kickstarter) and it's fun to watch. There's no great insight into Minecraft and you won't come away from it knowing more about Minecraft or Mojang or why Minecraft is so successful, but you will see the personalities of some of those involved and things about the community and the things people have done. If you're a fan of Minecraft it's definitely worth watching (but it isn't a Minecraft equivalent of "Indie Game: The Movie")
I think 2PProduction's documentary of the development of the Double Fine Adventure provides more insight into game development. (You can still back them and get access to the episodes.) A lot of the very interesting things had already happened when they started filming the Minecraft documentary so it cannot provide the same deep look.
The Double Fine documentary is excellent. At this point I really care not one bit about how the actual game turns out, the documentary has been extremely rewarding. They really seem to show it all, warts and everything.