Oh, now that I just recently subscribed to lifetime maps from Garmin, you tell me this.
Attached are two comparison maps from max resolution of both the Garmin 2014 update and the OSM or Open Source Map. Both maps are running under the Garmin BaseCamp interface. I have to say for dual-sporting, the OSM maps (http://www.openstreetmap.org/) tend to offer more detail in terms of roads and trails. It is free too, which is an added plus.