I received two 8300s this morning and what a surprise, they both came with XM Radio Mobile pre-installed. You can demo the service for three days and then sign up @ $8.99 per month.
Genres:
Preview
Pop, Hits & Dance
Rock
Decades
Country
Hip Hop & Urban
Jazz & Blues
Latin
Rock
You are warned a couple of times about having an unlimited data plan to use it probably because it streams over EDGE.
Sound quality is on par with music streamed over the Internet. A plus with the 8300 is the ability to plug in standard 3.5mm headphones.