Garmin 478GPS has charts?
Trying to find a good GPS (nonfixed mount) and noticed the Garmin 275 and 478. The only difference I can see in the two (other than price) is the XM radio and maybe the charts that come pre-loaded. Looks like the 275 only has general marine charts... not the true detail so you would have to buy a card. However, it looks like the 478 includes the good charts that you could actually use for coastal navigation because they have enough detail... its hard to tell from the specs and pictures because they always discuss the upgraded cards (if you look at fine print on th 275 it says with optional blue chart). Anyway, trying to figure out what you get out of the box vs with upgraded chart cards. Any help would be appreciated.