small nit: Technically, the lower half of main campus is within the Boston City limits. But yes, green, leafy campus with suburban feel.
Plenty of parties around for those that wish to partake, but many do not, particularly premeds*. Non-partiers head into the City for dinner and a movie, or go to a night hockey game to cheer, workout, and the like.
If she liked them both, choose BC. The Core will benefit her greatly in whichever field she chooses.
Check out the new Neuro major. (My D had to make up her own a few years back.)
*Getting A’s in lab courses requires commitment at every college, so social life for premeds is just not the same as it is for say, a marketing major.