Because I've actually read all the books several times and knowing that this was based upon a graphic novel, I was prepared to be offended. But though this Holmes and Watson are not the literary ones, the writers obviously know the source they're drawing from. Holmes is almost too eccentric and low-life and has what I call the Aragorn Syndrome-I kept wanting him to pause and take a bath and wash his hair. Watson is much more an equal partner with Holmes than his literary counterpart and they're both up for a good fight.
I really liked the art direction-London was just as filthy and sooty and it should have been. And I enjoyed the unique places they chose to do the action in-a shipyard and slaughterhouse among others.