You have 3 choices: regular, 3D and 3D IMAX but you have no excuses NOT to see this amazing movie. With 3D, the theater experience is back and you will love the lush scenery, the vertigo-inducing adventure and the smash-em-up action. There are some criticisms of the plot being too much like Dances With Wolves but actually I didn't mind that at all. Watch the faces: that's the key to enjoying this new technology. Plan to see it more than once. We chose 3D and loved it.
Take it or leave it: it wasn't my choice but I went along with family. I don't prefer mysteries (don't read them either) but SH had some nice treatments of Holmes' thinking. The period London was dark and brooding, probably perfect for this genre. The family members with me seemed to like it well enough. The young men in the family liked the fact that Holmes "called his shots" in his thinking before fights. That was pretty cool. Appropriate set up for sequels but I probably won't go.