I'll try to explain it to you.
The digital music sounds better
The few times I've tried to listen to XM, everything sounds like overly-compressed MP3 files (tinny and muddy; e.g. cymbals that go "squish, squish").
Sure, the frequency range is better than FM. That just means I get to hear the downside of digital compression. It's that compression which causes no MP3s to sound as good as CDs. Good music MP3s (at least 192 Kbps) are tolerable but, at least when I've listened to it, XM sounds like bad MP3s (perhaps 64 Kbps).
Regardless, if you're generally satisfied with the sound of MP3s, you're probably satisfied with the sound of XM, and I'm happy for you.
Have you listened to HDRadio yet?
Look, I don't think XM is CD quality, but it is better than AM or FM. Maybe the new HD radio will be better, but I don't know.
Thats what I'm comparing it to, Radio, not CD's.
And compared to terrestrial radio XM is far better quality, incredibly more diverse in its musical offerings, and commercial free. Not to mention it works nationwide.
Then when you add in all of the extras like Fox News/Cnn/msnbc simulcasting, Speciality channels like High Voltage (Opie and Anthony, Ron and Fez), MLB, Nascar, etc. There is NO comparison to regular radio.
Comparing XM to CD's is silly. Comparing XM to FM is a valid comparison where XM wins out on every catagory except for end user cost.
In the Vette I have XM, DVD, CD, AM/FM, my iPod Nano, shortwave, CB, a scanner, OnStar, and GPS nav.
(The only thing I don't have is a cassette or 8-track LOL)
Each is a "tool" in its own right, and I love having all of them.
I will not give up XM - worth every penny to me.