If you enjoy Sherlock Holmes, and you haven't seen this picture, you are doing yourself a disservice. As you can note by the many reviews, it is very Sherlockian. No small wonder: it appears to be a retelling of the Holmes story "A Scandal In Bohemia." It borrows the skeleton of the original story - which provides us with the comfortable old paradigm - but it veers from the source material enough to make it feel entirely fresh. Which is cool.
Also, it is interesting from a visual standpoint, which lends credibility to Sherlock's quote (from yet another story) that "Art in the blood is liable to take the strangest forms," considering Jake Kasdan's paternity. In this case, it might be better to amend the quote to "Art in the blood can't help but reveal itself." It's a pretty looking film, and the camera is in the hands of someone who understands how to use it as a narrative device.
Even those who haven't read every Sherlock Holmes story available will possibly like this, because I think most people like to watch stories about really, really smart people who figure stuff out . . . particularly when those smart people have a difficult time keeping themselves together, despite their intelligence.
The comparison to Sherlock Holmes wouldn't be quite complete without pointing out that this movie is very sequel-worthy ... and I hope that its makers finally arrive at the same conclusion.