Nicodemus: Learned Jewish pharisee, man.
Woman: Despised (by Jews) and relatively ignorant (of Jewish law) Samaritan woman.
Nicodemus: Comes to Jesus at night planning to speak with him. He comes at night, perhaps, to hide his visit from other observers.
Woman: Comes to the well during the day not knowing he is there. She comes to this well during the day, even though it is not the closest one to Sychar--according to Edersheim--and comes alone. This was probably unusual for women of the time. Perhaps she came alone because her reputation as a "lose woman" made her a sort of outcast with the other women in her community. Although, Edersheim points out that we really don't know if her past five husbands died or that she's necessarily "living in sin" with the current man.
Nicodemus: Knows who Jesus is and seeks him out. Implies he represents others, and that they know he is "from God".
Woman: Doesn't know who he is, and Jesus speaks to her first.
Nicodemus: Misunderstands when Jesus says "unless a person is born from above, he cannot see the kingdom of God." as "unless a person is born again...", the word, an'othen, meaning both "from above" and "again." He takes Jesus literally, posing the question, "can a man enter his mother's womb a second time?"
Woman: Misunderstands when Jesus talks about living water. "How will you get it? You have no bucket and the well is deep?" and "Give me this living water so I won't have to come to this well again and draw water." She takes him more literally, just as did Nicodemus.
Nicodemus: Jesus talks to him about being born of water and of the spirit. The language makes clear this is a single birth consisting of both water and spirit, and that it enables one to enter the kingdom of God. Nicodemus response is "how can these things be?"
Woman: Jesus talks to her about living water that gives eternal life. The woman's response is, "give it to me."
Nicodemus: His literal response and Jesus' answer is followed by a "dim search after higher meaning and spiritual reality" (Edersheim). "How can this be?"
Woman: Her followup also contains a grain of spiritual inquiry. "Are you greater than our father, Jacob?"
Nicodemus: Jesus rebukes him, and by extension the Jewish leaders of the time. "Are you a teacher of Israel, and yet you do not understand these things?" implying that they should understand them, based on their knowledge of the scriptures. Jesus teaching to Nicodemus is at an end; Nicodemus acknowledged the miracles show Jesus is from God; Nicodemus knows the scriptures; Nicodemus still fails to accept what it means about Jesus identity.
Woman: She has no previous knowledge to go upon and Jesus answers her gently, further explaining what he means by living water, although she still doesn't grasp the spiritual import and who he is. But she wants what he has. He replies with a sign.
Nicodemus: He comes to Jesus admitting he is from God because of the miracles/signs he performed, and his background should make the truth of Jesus words and his identity as the messiah clear, yet Nicodemus and his like fail to understand and believe.
Woman: She comes knowing nothing and with no background knowledge of Jesus, yet a single sign--that of him knowing her past and present situation--is enough for her to recognize that he could be the messiah and to go and convince others to come and see.
Nicodemus: Acknowledges Jesus as a rabbi performing miraculous signs and from God, yet fails utterly to comprehend or accept his teaching.
Woman: Immediately realizes, based on the single sign, that Jesus must be, at the very least, a prophet, and asks him a nagging Samaritan question about the location of worship. His answer, combined with the sign, lead her to give real weight to his claim of being the messiah, so much so that she drops what she is doing ("the woman left her water jar") and goes to get everyone else to come and see.
This pair of stories must have clearly illustrated to John's earliest readers a stark contrast between the learned, rejecting Jewish leaders and the unlearned, accepting Others. The learned Jews reject. The Samaritans, and next a royal servant of Herod the Tetrarch, accept.