Hmmm... here is an exerpt from Amazon's review of a Sirius reciever which you can see in its entirety here
. It pretty much says exactly what we've been discussing here.
Beyond the reception issue, the only other major drawback is sound quality, which some may find subpar. Sirius describes its sound as "digital quality," a euphemism for "digital audio with a bitrate so low that we don't want to scare people by revealing what it is." Whatever it is, its character is very close to what you'd hear from 96 kbps MP3--clear and listenable, but lacking depth, fullness, high-frequency extension, and dynamic range (though radio's always been super compressed). Your awareness of these shortcomings will depend to some degree on the caliber of your playback system. We noted that the classical stations seem to have better sound than the rock/pop stations.