Most of the stations are the same. There are just a few stations that one has that the other does not.
XM stations not on Sirius that you can purchase as an add on package (you can get all of these if you purchase the best of XM - except for the MLB game channels):
- Oprah radio
- MLB Home Plate
- MLB Game channels (not available with best of XM, but coming soon)
- NBA Game channels
- Virus
- NHL Home Ice
- PGA Tour Network
- College Sports Game channel
- XM Public Radio
- Indy Car Series channels
Sirius Channels not on XM that you can purchase as an add on package (you can get all of these channels if you purchase the best of Sirius):
- Howard Stern
- NFL Network
- NFL game channels
- Nascar Radio
- Martha Stewart
- Playboy
- Sirius College Sports Network