The 640 could/should have been so much better, had Garmin enabled the XM Weather capability in Automotive mode, in addition to the Marine mode, which does support XM Weather (WHY would they do such a stupid thing?!), and kept the Tracks/Tracks Management feature of the 276C/378/478 models, which are also geared toward Marine/Auto users. The unbelievable thing is that these missing features are all features that Garmin has implemented in older units - it is baffling why they would eliminate them in newer models, particularly at a time when this basic GPS functionality in the 640 is so widely available in smartphones. They also reduced the number of saved Routes. As the 640 is currently configured, I will stick to my trusty 478 for a long time, despite the fact that I would have liked to upgrade to a larger screen and updated GPS receiver technology found in the 640.