To be honest I thought this was just an OK story. Not really that special. Started off as a promising whodunnit but the second half of the story abandoned that whole concept and made it into a fairly basic "stalker" thriller instead.
Don't get me wrong, it was well written, and I liked the characters and the bad guy. But I think it was a mistake to abandon the mystery element. The ending was a bit of a let down, but I can't give too much away by saying why. Lets just say it could have been very good, but was ultimately just OK.
The way the plot developed she could have gone for some breathtakingly good twists and turns, but instead she went for the semi-predictable and downright disappointing events instead.