BMC alum here – what I really appreciated is that BMC is very collaborative, not competitive atmosphere in terms of academics, and I think that is reflected in the openness and warmth you experienced on campus. The Honor Code is not just an academic “no cheating” but something which shapes the way students treat each other on campus, in the dorms etc. With the course options at H’ford along with BMC, it is a vibrant, easy academic collaboration. As you have probably heard, course times are staggered on the two campuses so that students can get from one campus to the other easily on the Blue Bus to take classes on both. Also, certainly the towns of Bryn Mawr and Haverford are easily accessible to students, Bryn Mawr is 2 blocks from campus. You can argue about the pros and cons of Main Line Philadelphia, but there are movie theaters, restaurants, shopping etc. right there, with Philly of course a quick train ride.
It sounds like you are responding to very real difference in your reaction to being on campus at each school. As a parent, I have come to accept that its important to respect that in a prospective student’s response. Visiting schools over spring break with my younger son, he had real reactions to schools that were based on intangibles, and maybe they could not be rationally explained, but it just didn’t feel like home. As crazy as it makes me (“what do you mean you didn’t like X? Its a match, blah blah blah”) he’s the one experiencing it as a prospie, not me.
Good luck, you will have a wonderful education at either school, the challenge is to figure out which school feels like home in which you can grow as a young person.