The GPSMAP 67i comes preloaded with TopoActive mapping. The quality of the coverage will depend on the region. Urban areas will typically be more developed while coverage in rural areas may not be very good. TopoActive Maps are a Garmin OpenStreetMap Product. Scale detail can vary from 1:24K or better in major urban areas to much higher scales in more rural areas. For more information on the preloaded mapping, please see TopoActive Maps on GPSMAP Handhelds. 

The TOPO US 24K series provides more consistent topographic information than the TopoActive mapping, specifically a 1:24K scale map of the entire region. It also allows for navigation in the automobile, motorcycle, and ATV/off road driving activity types, something which is not supported for the TopoActive maps. You may find the comparisons at Choosing and Purchasing a Map for Your Outdoor Handheld helpful.