I am a late-blooming Apple Fanboy, but their stock performance enhances the romance.
Per the "other" thread, I am a really big fan of the iPad for navigation. When I bought my boat, I used iSailor and accompanying charts
to get the boat from Cleveland to Toronto. It sure was comforting to be able to see the little pointer in the middle of the lake in the middle of the night, when there was nearly nothing for visual reference.
The battery life is okay, but we have installed power ports inside the cabin and at the helm. The sunlight viz in less than perfect, but certainly workable or better.
The great thing of course is that, depending on the software, the vector charting is AMAZING - and so intuitive, you can work the software in minutes. The second great thing is that you possibly already have one; millions do. The third great thing is the myriad of other uses for the device. You can give it to kids to amuse them, you can get your Email, you can store all your favourite galley recipes, you can watch stored movies
or stream them from Netflix. You can listen to music, look at your photos, it just goes on and on.
No, you don't need a data plan to use it as a plotter.