In terms of Customer Service and technical support XM Radio by a landslide. Recently activated a Sirius radio and after a brief period of time experienced audio dropouts, called Sirius expecting help and was told if it didn,t work they would gladly cancel my service. Purchased XM, same problem this time CS referred me to a XM Technical support person who spend some 20 minutes on the phone walking me through the problem, needless to say problem Solved. Way to go XM. IMO a great service, great product.