Actually Jack,
unless I've missed something, Carl's right. I believe the Bushnell unit is terra only and has no marine charts on it. It may not even be equipped to load them. The graphic they show in their ad appears to be NEXRAD which I believe is ground-based composite Doppler, not satellite. It's still very useful (I have it) but satellite imagery would include things like infrared, vapor, and others. It doesn't look like that $17 service will provide satellite feeds or any number of other things you might find handy out on the water. If portability is a key ingredient then the Garmin 478 is a wonderful piece. It's preloaded with all the charts for the US plus Bahamas and more. In auto (as in car) mode it has all road maps as well as location, directions and particulars on just about any store or agency you'll need. The XM service is more. $30 - $50/month depending on what features you desire. It can be turned on and off as needed. I can get real time buoy reports, isobar maps, graphic forecasts, animated NEXRAD, satellite imagery and more. The 478 is about a grand. The XM antennae is separate, external and about $150. Personally, when I'm on the water I think it's a bargain. It helped us stay out of some problem weather a few times this last June. It was nice to be able to see where a particular storm cell or system was headed. It is NOT a replacement for onboard radar. My unit will NOT tell where that unlit shrimp boat is. it will NOT tell me how far an unlit outer marker had dragged in the middle of a pitch black night. Hope this helps.
