I need to replace my GPS, and the maps are more critical to me than than the unit. I'll likely purchase Garmin, Lowrance, or Humminbird, but want to base my purchase on the maps. I don't need special sonar imaging features. As you've pointed out many times, the base maps lack detail, and the best maps for the marsh are based on USGS topographical data. Some of the previous posted information appears to be no longer relevant due to changes from the vendors. Could you provide some guidance on current information as to which maps are top tier? (e.g. Garmin Lake Ultra Vs Lowrance maps versus standard maps vs whatever)