Probably the usual response to it is not "you know, maybe I should re-read the Pippi Longstocking series."
Structurally it's similar to Naoki Urasawa's
Monster
: a thriller plot with several characters separately working on a cold-case crime with present-day implications, eventually pooling their resources; the eccentric but ethical old tycoon bereaved by the loss of a child many years ago, unleashing dangerous forces in an unexpected end-of-life act of humanity; the use of the Holocaust as a sort of primordial source of evil, a few years in the grave, but still in living memory and still somehow a threat; and the fact that the story exists as a vehicle for the author's investigation of his personal image of evil. Larsson's is rape, Urasawa's is child abuse.
Larsson is significantly less complex and a little less willing to be nice than is Urasawa. Salander and Blomkvist want to scourge their evildoers from the face of the earth, while Dr. Tenma and Nina view everything in a more internal way, convinced of their own complicity in the morass they've discovered (though they have none in any real sense; Urasawa doesn't let things get that heavy) and determined to redeem some part of it. Urasawa would end the cycle of violence by healing the abusers, while Larsson would prefer to kill them all.
It's interesting and kind of cheap that Salander kills two people and ruins the life of a third passively, setting their worst instincts loose and letting them do the work themselves. It's kind of the Disney hero move. Tenma and Nina take more responsibility there.
I don't buy Salander as a character; she has very little apparent self-knowledge, yet is able to penetrate to other people's innermost souls very quickly and easily. Those two things don't usually go together. The way she talks about computers is silly about 50-60% the time. I think Larsson probably had help from an actual nerd for some parts of the book, but wrote others himself. The journalism sections sound more reasonable to me - not that I know anything about that, but Larsson was a journalist himself, so I adjudge it to be possible that those parts are silly less than 50-60% of the time.
I'm not sure whether this is actually the first long-form piece of fiction Larssen wrote, but it reads like it. In addition to the inconsistency of her characterization, Salander has a personal subplot that ends up dead-ending almost immediately, disconnected from the rest of the book in every sense except for theme. Scene changes are very abrupt, and conversations end in strange places because he wants to get on to the next scene.
I have no way of knowing, but I don't really feel like the problem is the translation; I think the prose was probably just kind of awkward to begin with. Larssen does that thing where he spends a lot of time pounding in descriptions of mundane tasks like doing dishes and putting on coats, to keep the story from feeling like it's floating a couple of inches off the ground. He doesn't always succeed - honestly,
Twilight did it better. And it's obvious who the villain is almost from the first time s/he's mentioned, though some people might view that as a feature rather than a bug.
Basically I'm saying that if you can only read one of the two, you should definitely read
Monster.