<p>Obviously both are outstanding schools and I am sure you would be happy and successful at both institutions.<br>
If your primary worry is that Vanderbilt is “too Southern” I think it is misplaced–yes, Vanderbilt is in the South but that is not a bad thing (The majority of the students at Vandy are not from the south and even those who are might not be what would fit the stereotype-- one of my daughter’s friend from TN actually grew up in Indiana and another from TN was raised in Miami, FL and even though on the map my daughter would be considered “from the South” she was raised by parents from north of the Mason Dixon Line.) I think people worry way too much about the “southern” stereotype.
Having lived in Connecticut and northern Indiana (during one winter) and Nashville, I would far rather have a Nashville winter than one in the upper mid-west, the wind was brutal; even southern Connecticut was better than that 
A brief anecdote–when the families were eating at the freshman Commons the day of move-in, I was in line next to a young man who was an older sibling–he looked around the cafeteria at the Commons and said something like: “wow, this is great, I wished I’d looked at applying here to Vanderbilt” He was wearing a Northwestern tee shirt.</p>