A.) Zero commercial music presentation.
Spending time with this makes spending time with commerical radio more difficult.
B.) The radio tells me when my favorite artists are on anywhere on the XM system – even channels I don't listen to – and lets me click over to listen with 1 button push.
This is the type of user-centric feature that sends chills down commerical radio programmers spines. But I bet if you ask people at random if this feature would enhance their radio experience – most would say yes.