The difference between the two, is that Rei is reserved and Rei Q is clueless.
Rei is intelligent, reflective and capable, but reserved. She doesn't say much, and every time she does, it's damned well worth listening to because it implies a whole lot of stuff, or has some kind of deep insight into either herself, the world, or the others.
Rei Q is clueless. She doesn't say much, and every time she does, it's not really worth listening to because all it does is show ignorance. It shows that she doesn't know, that she's blank and clueless.
Emotionally, what she has is fear and confusion. Which is understandable, but those are the differences.
If Rei asks "What am I?", it's a broad question which involves analyzing herself, others, and the world around her. She does that in her monologue among other places.
If Rei Q asks "What am I?", it's not to independently find an answer to a question everyone should ask themselves not just Rei, it's because she's afraid and has no clue, it's purely a reaction.
>>2159204see above. They don't qualify as robotic on nearly the same level.
You wouldn't see Rei say "I only follow orders.", and then nothing more. Not without reason. There is no reason for Rei Q, she's just droning along for unknown reasons since her character has no motivation or background whatsoever.
