Ultimately this amounts to a movie about Lisbeth's trial with a little intrigue and action thrown in but the part that makes it compelling is that all the things you've watched Lisbeth go through in the last two films come to a head. Without giving too much away we are finally able to see Lisbeth benefit from her take no prisoners attitude and come out on top to a certain extent which is incredibly satisfying.
However what the movie does well with respect to it's karmic attitude towards Lisbeth, also comes off in this instance as a little self serving and unlikely based on the context which has been set up in the rest of the series. That said I'm willing to forgive a little pandering to the audience if only because any other ending would have been insincere. What's more, the last scene manages to be surprising and honest enough that it also counteracts the awkwardness of some of the resolutions.
All in all the series is definitely worth watching and makes me want to have a look at the books. I'm hoping that a little of the pandering can be explained by the translation to a new medium but ultimately I don't really care. This series is the source of one of the most compelling (and well acted) heroines in recent memory and is entirely worth a viewing. While neither of the sequels can outstrip the original film, they are of a better quality than a good deal of the current offerings out there.