Hey there. I don't have too much familiarity with Mission Hill as I lived in the Fenway area when I was in Boston, though I did have plenty of friends who lived there. None of them stayed there more than a year. They all ponied up another $100 to $300 bucks a month and moved to Brighton/Allston area.
From the few times that I've been there, I personally wouldn't want to be riding my bike through there at 2AM.