BostonBusMap

Highly recommend if you are a bus rider in the area. Have found it pretty accurate for minutes away in Somerville and Cambridge but during rush hours or construction it is good to switch to viewing the bus locations occasionally to see if they are stuck. Definitely worth starring your frequently used stops.

Good interface, no big complaints except that it often fails to report delays, especially close to either end of a route (which may be the fault of the MBTA rather than the app) and that it's basically impossible to report a problem (disappearing buses, etc).

Wish it was more like life360, it doesn't update frequently enough. You should be able to see the bus moving in the app in close to real time. Instead it periodically updates the position of the bus only to be about 2-5 minutes behind where it really is.