Had a legend for a while, use it for mountain biking, trigpointing, geocaching but the ONLY maps you can load into it are the Garmin mapsource ones. The accuracy of the maps isn't brilliant and has no topo info like OS maps. On the Garmin website you can see a fully working map review, just select the product and click on the map to zoom in. Once you have the software You select the area you want and load the required tiles. I can get north Wales, Lancs/merseyside and cumbria in at the same time (only 8MB memory) But they are adequate and a vast improvement on having a non map gps like the yellow etrex. You can of course hook up the Legend to a laptop and use it with a chartplotter on your boat!
try here for software http://www.globalpositioningsystems.co.uk/