Read it and weep
http://www.hydrogenaudio.org/forums/index.php?showtopic=64686
http://news.cnet.com/8301-13645_3-57471903-47/sirius-satellite-radio-still-sounds-awful-after-all-these-years/
Satellite radio had promise, but the usual market BS of having two incompatible standards, rather than having an open inter-operable standard,
and shock horror competing on price / service / quality.
So given finite bandwidth from the birds, and the marketing message that More Channels (N) was better than the resulting 1/N average bandwidth,
what do you expect.
If you're a long distance trucker, travel in the satellite footprint with line of sight, when out of cell/radio coverage, it has its place. But audio fidelity is not a strong point. It shouldn't be harder to put together a better sounding stored media solution these days.
more chat here http://www.avsforum.com/f/101/xm-and-sirius-satellite-radio