If you want a larger format or urban setting, the decision is easy. Academics at both will be top notch. However, Penn (especially pre-profressional)/ Wharton undergrad) has a reputation as being very competitive, whereas schools like Williams and Amherst are very collaborative. In terms of placement in professional schools, Williams is phenomenal. They place large numbers (pro rata) at the top law schools, business schools, B schools and PhD programs. Anecdotally, in my son’s class at Harvard Law School there were I, I recall, at least 5 or 6 Williams grads out of a class of ~500 and fewer Penn grads (even though it is a larger school). For what it’s worth, Williams through 2014 had 35 Rhodes Scholars, while Penn had 19, again despite the larger format. I have an affiliation with neither–just my observations. This is not to diminish Penn’s obvious prestige and quality. I do know from folks who went to Williams that the school will move heaven and earth for its students (including research and internship opportunities), and the alumni likewise are very supportive of graduates in a variety of ways. Williams also fosters a community amongst students of different backgrounds and interests. You will not suffer for opportunities at or after either. Choose where you would enjoy 4 years the most. There will not be an appreciable difference in opportunities unless you want easy access to a city.