I spoke to Garmin Tech support last evening concerning the 378's inability to accept PC generated routes. It is true that this unit will not...something to do with overlapping water and land maps.
An assumption was made that the 478 would not accept PC generated routes either. But that apparently is incorrect. Per Garmin, the 478 will accept your PC generated routes. The conflict between the land and water maps does not occur with this unit.
So, if you're in the market for a GPS that has all maps pre-loaded, XM radio, XM NEXRAD weather, and the desire to make up routes on your PC, the 478 might be a good choice.
An assumption was made that the 478 would not accept PC generated routes either. But that apparently is incorrect. Per Garmin, the 478 will accept your PC generated routes. The conflict between the land and water maps does not occur with this unit.
So, if you're in the market for a GPS that has all maps pre-loaded, XM radio, XM NEXRAD weather, and the desire to make up routes on your PC, the 478 might be a good choice.