Coursework intensity, networking, opportunities (internships, job offers, etc), atmosphere, etc.
I am actually not sure that UPenn has this major. It's not on their website: https://ugradadm.seas.upenn.edu/majors-program-options/bachelor-of-science-in-engineering-bse/. We also don't have it in our database: https://blog.collegevine.com/us-colleges-with-aerospace-engineering-major/.
Maybe you're thinking of Penn State instead of UPenn? https://www.aero.psu.edu/
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