how does it compare to original?
I think both are good films.
I didn't compare the two (in my review) because I don't consider them the same thing. Working with different budgets, different actors, playing to different audiences. Rapace and Rooney are both extremely impressive in their portrayals of Salander. I think Daniel Craig was a better Blomkqvuist. Skarsgaard is the better Martin Vanger. It's really the difference between a big film and a small film.
Both were well done, but I enjoyed Fincher's version more and it probably is the better film. Pretty similar to how I felt about the Let the Right One In films.
All I can say is go see it.