The plot isn't blow-away twisty. I felt it was mostly fairly predictable, they give too many clues for a mind bent by many years of SR. Because of this I found it to feel a bit slow getting past the parts that were already telegraphed to me. Sure the SO missed the meaning of a lot of stuff until much later in the movie, but she's kinda slow at that sort of thing. She didn't get The Sixth Sense till a number of minutes past the ring dropping on the floor.
However it is a nice story, is a very well crafted movie, and Jodie Foster's character is one of the best examples of a pure Face I've seen in some time. I give it 8 of 10 stars on the 'Runnerific Scale.