Jehovah’s Witnesses have been successful in attracting members of other churches in the Western world, mainly Catholic.
Here in the US, JWs hardly make a convert from Evangelical Protestants. Their growth comes from immigrants mainly.
JWs have a dismal record in countries where Islam predominates. With the exception of a few countries like Japan, Philippines, and Korea, their record in making converts in the Middle and Far East are very poor. Even in Israel, after so many decades in presence there, they have only like 15 hundred publishers. In Bangladesh, they only have one publisher for every 7 thousand people (7,000).