Except that with a GPS the map function is near useless.

Ozzy, YOU find it useless because you essentially have a BIG COLOR mapping GPS
on your boat already. With only charts aboard, the mapping GPS handheld is
nice...another level of info. It's comforting to see that the Mapping GPS
agrees with what we "think" we're seeing along with what's on the chart. As
Bill pointed out, redundancy.
I'm sure when I set up the laptop, I won't use the map feature often.

RB