I think anyone who leaves now is like anyone who left in the past- they do not believe the core beliefs of JWs, especially in regards to organizational structure. Most don't want to be apostates, they just are looking for a different church.
The various exJW sites can help those who are dealing with the fear and confusion that comes from stepping away from a group that uses fear to control people. It's good to have a place to turn to, where you can understand that you're not a bad person for wanting to think for yourself.