Yes! ...and no...
I have the XM-Radio version using WxWorx which has been around a bit longer and is extremely similar. The good news: I've been able to receive the data feed (and listen to Sirius music) everywhere from the great lakes, all the way up to Labrador and out into the Bahamas. And yes, the ability to "see" storm activity far over the horizon has been wonderful and allowed us to dodge some good poundings. The bad news: The NEXRAD radar that allows you to see the storm activity only covers the Continental US. So, even though you can get the signals here in Nova Scotia, or down in the Bahamas, you can't see the storm activity outside of the US. They also don't have the canadian marine forecasts. Its possible that the SIRIUS folks have the canadian data (there are a lot of sources for it, including canadian doppler radars) but in the carribean, and more than 50-100 miles off the US coast, there simply aren't any doppler radars installed so the system can't send the imagery to you.I find the systems to be great for knowing what is happing "now" but short on forecasting. Knowing what is happenning now and will be coming my way is helpful, but I find other sources much more useful for planning and forecasting.