There is a compass on the BMW versions but not the normal Garmin but as the compass on a gps only works when you are moving it is of limited use on a `road going' gps. There is the option on the 2720 to put a tiny compass arrow on the left of the map but, to be honest, its more of a gimmick than a useful tool.
Both on bike and backpacking, if I need to follow a bearing I use a magnetic compass.