Hi, I don't know much about Brown but I also got into BU's program (I haven't decided where I'm going yet). I went to undergrad in Boston and so let me paint a somewhat less antagonistic picture for you. Fair warning: I am originally from Canada - still a transplant but from a much less hospitable climate than California.
Boston is a lovely place to live for the following reasons:
- Easy to walk around
- Great shopping district
- Chinatown = amazing food for cheap
- Sporting events (even if you're not a baseball fan, Boston has hockey and basketball as well. Football is too far away.)
- Tons of college students and young professionals to meet and befriend
Things that aren't so great:
- The weather can be bad sometimes
- It's pretty expensive as cities go
- When the weather is bad, the MBTA stops working (it can be quite slow the rest of the time, as well)
- Townies can be mean and are best avoided
- Everything closes really early, even on the weekends
I absolutely loved living in Boston, even in spite of the cons. If you are prepared to make an effort to find hobbies and friends, and you're not super worried about living expenses, I would probably pick the better/more established school of public health.