I am considering buying an Etrex Legend kit that includes disks of topo maps(Mapsource?). Can anyone tell me how good these maps are. The salesman tells me they are USGS maps and I could zoom in for greater detail. Does anyone know how detailed these maps are, what the scale is, and whether they are worth the price? I am a great believer in 24000 scale USGS quad sheets and I am very skeptical of the usefulness of maps displayed on a two inch computer screen. Thanks for your help.