Actually I am quite pleased with the sound quality of XM service using a Polk tuner through a Benchmark DAC. Granted it is not nor do I think ever could be "CD quality" as claimed, but some formats (Jazz, Classical, Instrumental) sound pretty close. Format wise I think both are about the same from a music standpoint, X the differences like Stern or XM's version of anoying talk show hosts. I chose XM for home use due to the inclusion in my GM vehicle as I already had an account, and the fact that Polk was comming out with a home tuner with analog output to a DAC. Not sure if anyone has a similar tuner available for Sirius but I am sure if not they will soon.
