I would suggest starting with what you want to do with the GPS. If there is a particular waterway you travel most, or if you plan to use it in a particular region of the country. Then look at maps.
Some people want to use it only for navigation. Others want to use it for navigation and depth. I use mine for depth for fishing, but also to give me a general idea of depth for navigation. I hate moving around on a new lake and not knowing about that potential unmarked sandbar in the middle of the lake.
This particular model may do just that but it has no detail to the maps, no depth lines or depth contour maps and it has no ability to add them. So I think I would shy away from it. Hummingbird spent a ton obtaining Lakemaster. And now all new units have the ability to add, if not come pre-loaded with the lakemaster maps.
I would look for a unit that can take maps. Or go search for the maps you like and see which GPS models can use them. Once you find that, then you can look at the directions and find the ones that you can load easily with little hassle. It sounds backwards, but the application is driving the hardware, not the other way around.
Good luck!
1st year GPS: Lowrance H2O with Lakemaster SD card in the summer, Redpine Mapping for Snowmobile trails in the winter, LEI road maps for the motorcycle
2nd GPS: Garmin Nuvi for the car with lifetime map updates. Redpine mapping for snowmobile trails in the winter, Hope to use it on the bike as well
3rd GPS: Apple iPhone 4s, Navionics Marine and Water for lake maps and contours, Polaris Snowtrails for the winter, and "greatest Roads" for motorcycle trips.
There are lots of options.