So I have been contemplating the same issue.
I have open CPN
on my laptop
and just returned from a cruise
with my buddy Captain
Steve from Snead Island to Sarasota
and back. The return trip was in the dark from the Manatee Bridge and around to the front mark on the Manatee River up to Snead Island.
In this narrow dog leg channel you have no room for error as there are shoals with 2 feet of water
on a high tide on a good day.
wins hands down over open CPN
and the chartplotter
for the following reasons in our humble opinion.
Seamless transitioning from chart to chart
Quick & simple go to function using caliper button
Touch zoom in and zoom out in a dark cockpit
no looking for functions & buttons
Chart brightness is easliy changed for night vision by changing settings on the iPad
Based upon this real time test in a challenging navigation
exercise, I am going to purchase
an iPad and likely will load Navionics as well. I really liked the ease of use underway.