Don't worry about the chart
For the most part, a handheld GPS is only good for the way it was originally intended as just giving directions, and locations. When you try to put in a base chart as in a typical chartplotter today, by the time you get down to the detail you need, you are zoomed in too far and can't see everything that you need to see. It all comes from the size of the screen. Now, you go into some of the larger Handhelds, like the Big garmins, and the screen size allows you to get even better. My recommendation to you, is to buy a Garmin 76, 76cx, or 76 csx that will be supported for some time and don't plan on using the chart part, unless you are only sailing one reasonable area. If you will need more than one chart area, you will be spending more money than you need to.About the only thing I feel that the chart on most handhelds is useful for is scrolling around the map to set a waypoint or route without having to type in multiple numbers, not for actually getting there.