A Believer, I have not read through the responses so if someone has already said this it bears repeating. The Jehovah's Witnesses are a dictatorial religion that usurps Jesus' place as an intermediator from the Biblical perspective (BTW I'm not Christian).
It's all about glorifying the Watchtower as God's sole channel of communication. Listen carefully at their meetings and you'll pick up on their blasphemies. Their memorial service is about the best example I can think of. A meeting where no one partakes of the wine and crackers except an elite few which you would hardly fine in most congregations. In the real world of Christianity everyone partakes just as Jesus told his disciples.
This elitism of theirs is an insult to their god. In effect they're being told that they are not saved.