I use the Gold+ Emil. The platinum gives points of interest and some 3D overlays....I don't need nor want that.
I took this off the Navionics site.
"The marine Gold+ charts have depth contours, spot soundings, buoy information, obstruction information, show the chart in a paper like view (the water has different shades of coloring), the Xplain feature (which explains different icons on the chart), has major coastal roadways, NavPlanner compatible, enhanced port services & the availability of the free Fish'N Chip (offshore bathymetric information). The marine Platinum charts have the same information as the Gold+ charts but additional advanced "award winning" features such as Coastal Points-Of-Interest, Panoramic Port photos, geo-referenced Coast Pilot Books, top-down satellite photo overlay and 3D view for land & water."