The overlay is useful in two situations:
1. You don't have a large screen
. In this you have content in the same space and can see more at once. I have an E80 and use the overlay largely for this.
2. Its useful to see what harbor entrances and objects look like in good weather
so that you know what they will look like in bad weather
. If the GPS dies, you may still have radar and can navigate with that as well as DR.
I like it, but remember that there is a few second delay with GPS so the radar will be more current
than the GPS positioning..
S/V Black Diamond