I live up on ashmont hill and would regard the area as quite safe. I’ve never had an issue with packages being stolen and I haven’t seen any locked cars broken into( unlocked cars is a different story, lock your cars!) I walk to the restaurants on Dot Ave regularly at night and never had anyone bother me. The T is still the T so you get some issues but that’s not specific to ashmont. While my favorite restaurant, the ashmont Grill closed recently, There’s still plenty of great places to eat, and things to do around here. All in all I would say definitely consider it as the area only gets better and better every year and it’s a lot more affordable than many other areas in Boston