Also, for those not from the area, JP is indeed a "Boston neighborhood" but it's on the outskirts around parkland, the Arnold Arboretum, etc. and is about a 30 minute public transit ride [edit: on the Orange line not Green line]. So don't imagine this is in Boston in the way many might imagine. It probably has more in common with close in suburbs like Arlington than downtown.
Of course, the reason that Arlington doesn't have better transit links is that they didn't want it when the Red line was extended to Alewife. JP is certainly less suburban than Arlington but it also doesn't (to me) really feel like it's in "the city."
If I go into Cambridge after work, it takes me something like 45 minutes to get to Alewife near the Arlington line in pretty nominal reverse commute traffic. It takes me a good other half hour to go the last few miles. (And that's Cambridge. Boston would take even longer although I'd normally take a different route from my house)
I lived in a 6 bed unit on the top level of a 3-story duplex that had 4 people living on the ground floor. It was a massive house that allowed for ten non-related people to live together on a street filled with similar houses, lined with massive oak trees and a five minute walk from a lovely pond. Gorgeous neighborhood.
Edit: I’ll add that I never experienced any negative effects in JP that I’d associate with such dense living. Unlike the more rowdy student oriented neighborhoods like Allston that were far more rough and messy.