Sorta like cable TV compared to the regular programming that you get from an aerial.
NO commercials and a better choice of music...anything you want.
You can target one decade (like the 60's or 70's), go for soul, R&B, rock, jazz, blues, country, reggae, African, show tunes, movie soundtracks, European hits, new age disco, etc or go to any one type of music...over 100 channels to choose from.

I like the SOUND I get from mine, have it hooked up directly to my AIWA system here at home....can barely turn it up without the Super T-bass rattling the windows or waking the neighbours. The receiver is portable, and goes into my car OR the "boom box". Good for taking to the beach, the cabin, the motorhome, or working out in the garden.

Plus I like the electronic dance music and you just don't get that anywhere else down here, commercial-free.
The Roadie II is new as my tape deck burned out in my car, and rather than replace the CD unit; it was cheaper just to get the wireless. (The first XM satellite receiver worked off the tape deck, believe it or not).
Satellite radio was a Godsend here during the hurricanes when the power was out. Commercial free.