Read Combatting Cult Mind Control by Steve Hassan. The book is about the authors experience with The Moonies (nothing to do with JW's). They employ all four major components of mind control: Behavior Control, Thought Control, Emotional Control, and Information Control. The book changed my life and helped me realize they qualify to be grouped as a high-control cult.
Great comment by Rank&FileGuy. Same for me. I read that one before the Ray Franz books, so it was really my first book after realizing I needed to get out of the religion.
This issue is not as volatile as the heated debates between believers and atheists, but there are plenty of ex-JW's that don't want to call it a cult or want to remind us that most any religion can be defined as a cult. Fine and good.
I use the common modern meaning of "cult" and don't even bother with the single word, but use the Steve Hassan term, "dangerous mind-control cult." When people ask me what makes it such, I explain the BITE method and the shunning and the blood issue and how JW's have to consult their Watchtower before they have a thought on anything.
I think it disturbs some former members to think they were in something that turned out to be a cult. All I can say is that intelligence has nothing to do with it, and we were in a large cult far behind the Mormons and Scientologists in whackiness, but also way behind most other Doomsday cults so far in that we weren't asked to gather at some remote location for 1975 or the end of the 20th Century. But stay tuned to see if that ever happens.