We use an iPad and a couple of the nav apps listed in the article on our homemade houseboat's cruising on the Albemarle Sound, and couldn't be happier. They're very accurate, even without the BadElf GPS dongle, the planning functions are fast and intuitive, and there's a plethora of additional information available at our fingertips, even photos of marinas, all sorts of phone numbers, and updates on troublesome areas. Yes, there are paper charts at hand, but will you be shocked to learn that I never look at them? For an additional $35 or so per month (haven't checked lately) you can add 10-minute-old XM marine weather products to the screen. Nice, but I ditched XM's aviation service in favor of a different technology, so it's not part of our boat kit anymore, either. If we were long-distance cruisers, it sure would be.
Like thousands of other pilots, iPad is my copilot. I haven't looked at a paper aviation chart or updated approach plates by hand in years. My backups are all electronic, too.
Life is GOOD!