I'm a graduate of the US university system myself and am now a parent going through the Oxford application process with my daughter. The abovementioned tutorial system is the huge differentiator, in my view. In the US, at most universities your child will spend a ton of time in large lecture halls, particularly in the first couple of years. The type of learning will be very much like what she's probably had at school so far, namely, sit in class, listen, study and regurgitate. My daughter is very good at that and is shy, so she has managed to get through 14 years of school without raising her hand very much or generally interacting a ton with her teachers. The reason I'm so keen to see her end up at Oxford is that there's no escape. She will be forced to develop skills that are currently not her strengths because of the weekly tutorials which are with only 1-3 other students and the top-level professor. At most US universities, she would also have these smaller tutorial groups, except they'd be small like maybe 20 students, not 2, and they're with one of several graduate students who serve as teaching assistants for the lecturer, not the lecturer him or herself.