Though C-Map's richness in detail can get in the way, any confusion can be avoided by taking advantage of vector charting. To customize the data you want to see and add or delete layers of information, go to the menu, find the appropriate file, and then remove from the screen enough information to make the display less confusing or add information when needed.
Both the C-Map and Navionics menus are easy to use and about equally fast at accessing information. If you want to remove all depth markings other than those less than 10 meters, for example, go to the menu, call up the contour line file, and turn off all depths except ones less than 10 meters. The same can be done for other types of information displayed on the chart, such as text, sectors, or background colors.
C-Map and Navionics operate at about the same speed when working among menu pages, but C-Map is much slower than Navionics when going from one scale level to another. It might be because there's more information to process, but C-Map often takes six to eight seconds to do a screen redraw when going from one level to another; Navionics does it in about a second. Because the Navionics screen changes so quickly, it's easy to miss the scale level as it flashes on the screen. One point of contention here: Everyone thinks the scale level should be displayed onscreen at all times on both programs.
Both C-Map and Navionics have port service information directories, which list the various services available at harbors in the area, such as gas, diesel, ice, and water. An icon appears for each service. Put the cursor on the icon, hit enter, and you're shown what's available and where. We tested this for Rockland, and C-Map's listings were more extensive. In one case, Navionics didn't list a major marina.