I have the 378 and love it. The diff between the 376 and 378 is in fact that the 378 has alll maps preloaded so it would make sence to get rid of the 376 that you have to load the area you are going to.
The diff between the 378 and 478 is the 378 has inland lakes and navicable rivers showing things like bouys on the large rivers. The 478 has the coastal waterways (saltwater).
Skooter Are you sure you can load maps into the 478 I would think it would be the same as the 378 as far as the software is concerened.
The mapping is different between the two models.
The one you want is the 478, To quote:
Because of the unique way the map data has been combined and loaded, the GPSMAP 378 is not compatible with Garmin's City Navigator NT North America DVD, which is sold separately. For example, if you use this City Navigator NT DVD to plan routes on your computer and transfer them to the 378, the unit will recalculate each transferred route.
The 478, which costs less does not suffer the limitation
Also note that while the 376 came (comes, if you can find an NOH version) with the XM pod, that's an extra cost item with both the 478 ans 478.
I had been considering an upgrade from the 376C to the 378 because I can only put about 1/3 of the US on a 512 MB data card. As a truck driver this means dragging out the laptop to change the maps on the card every other day or dealing with the basemap in the unit. The reason for the 378 over the 478 is that inland lakes would be far more useful information than coastal waterways for me.
So in essence you can still use City Navigator NT to transfer routes and custom POI's to the 378, it will just recalculate the route? Since I just plan my trips on the GPS and have never used the City Navigator NT software to plan a route, I assume this limitation would not bother me. On the other hand, if I can't get updated maps into the unit every 2-3 years that would probably upset me. Anyone know for sure if the 378 basemap (City Navigator NT) can or can not be updated when new maps become available?
David
p.s. I absolutely love the Nexrad available through XM MW (Not the NavWeather crap), but the $30/month for the fisherman package would be hard to justify if you didn't use it every day like I do.