Although this novel is not quite the body-count thriller one would expect from the product description (most of the murders mentioned in it are backstory, and barely sketched-out in the book itself) and the plot is fairly routine, it has other attractions to recommend it to readers.
It is an interesting story competently written in plain, clear language, and possesses a genuine sense of momentum to carry the reader along. Above all else, it has Gloria, the villain of the piece. The internal thoughts of some of the other characters are sometimes a little too simplistic or childlike, perhaps, and some of the interactions and actions (or inactions in some cases) occasionally don't ring true. (For example, the married couple Gloria victimises, being the people they are, would certainly have called the police in to investigate.) But these are small quibbles which generally do not detract from the entertainment.
I would recommend this novel for the character of Gloria alone, which is a wonderful portrait of the bitter, negative and small-minded banality of real-world evil.