While some may not toally agree with this opinion, the quickest least painful and upbuilding way I have seen and heard of people being able to help JWs become Ex-Jws and be able to thrive afterwards is if they are confronted with Christian Witness.
There is a process in helping a JW become an Ex-JW. First you must take away the false authority that is over them (the Watchtower). This is done by only using Watchtower publications alone (no Bible!!!) and going photocopy by photocopy showing where they have lied and are currently lying. Having a good 20-30 all out lies straight from their publications is a great way to tear down the Watchtower Society and proove it to be a false authority.
But from what I can tell and understand is that since JWs really want to view the Bible as their authority (but in reality the WT is), once that WT power is broken the Bible then CAN become the authority and a JW will open up to a Christian message that takes them right to Jesus. If a JW is confronted with all of this negatvie stuff about their religion and a BETTER hope cannot replace the one they allready have then there can be alot of problems. Depression and a feeling of worthlessness can result. I really feel the proper motivation is to bring them something better, more free, and personal.
Many on this board have tried a varitey of things in order to help a person out. I have found that the #1 thing is to go in fast, strong, and with a purpose. You must be prepared to totally take down the Watchtower in one sitting. Enough so that the person will have a change of heart and be willing to really examine the WT. If you don't go in with enough documents, focus to much on Bible interpretation, or keep the conversation to subtle progress will be difficult.