Um, I live in Boston and I have to say that this is a pretty liberal city.
BC used to be a mostly Catholic college, but over the years it has diversified a lot. It’s a strong liberal arts and good sports college.
BU is in my opinion the better school. It has a very strong music and fine arts department and the courses all around seem more diverse. Everyone I know who goes to BU adores it.
BoCo (Boston Conservatory) is different from those too because it’s obviously a music conservatory. I’ve actually heard (and agree) that New England Conservatory in Boston is the stronger of the two conservatories, but BoCo is still an excellent school.
It really depends on what you’re looking for in a college. If you don’t want a strictly musical setting, I would go with BU. If you want a strong music program, than the only one I wouldn’t recommend is BC, but if you want just a strong liberal arts school, either BC or BU would be good.
~And let us try, before we die, to make some sense of life~