TTWSYF - I have had many an argument on the streets regarding the NWT bibles to the JWs, it gets nowhere, I have argued for 40 minutes over translations, and find it's fruitless.
They argue that the KJV has errors, it doesn't display God's name, it's a "trinitarian Bible" (obviously they don't agree with the trinity). It's pointless :-( we met with JWs and they didn't want to discuss doctrine, they only wanted to discuss bibles. I have explained about Westcott and Hort, and they deny outright, even when I present evidence.
One of the other questions they scratch their head at is
1) Is Jesus your mediator? They say "Yes" but their website says "No" and they get confused..
2) If Jesus is not God, and there is only one True God, Isaiah 9:6 explains that Jesus is a "mighty God" therefore, is he a true God or false God, if there is only one true God? They cannot answer that one.