I've always thought that personal experiences are really powerful - there's a reason the WTS use them so much in literature and from the platform.
Remember, you want to help people who have been indoctrinated to think we're out to get them. Seeing that we're just like them, have gone through the same challenges they may be going through and most importantly have come out the other side happy, living successful lives is one of the most powerful things possible.
Just the notion that people who leave the WTS don't turn into deranged dug taking immoral crazies (well, not all of us) and that you can leave with your family intact and all be happier will knock the legs out of what they have been led to believe.
Also, that the issues they have endured in their local congregation are not isolated or unique, it's what has happened to many many people.
The anger-messages calling the WTS names and bad-mouthing JWs doesn't help anyone and simply plays into the WTS narrative, but it's what some who leave get their needle stuck on.