Bitter? No, not anymore. I still, however, become angry when I read about the pain that is constantly inflicted on good people who want nothing more than to serve God and help their fellow human beings.
Yes, there are those JWs who seem to be more intent on contemplating billions of rotting corpses while they gleefully ransack all the material goods they feel they will be owed for making such great sacrifices now. Those tend to be the JWs who are happy as JWs.
JWs who become bitter and leave are those, IMO, who genuinely care about others and who are very affected by the gross abuses they see occurring in "God's" organization.
Coming here to vent, bitch, scream and eventually heal is a good thing. No one should be denied this.