In your case if you've heard both music chanels which your of more interest, then go with the one you like best. But make sure to let the company know that if they add commercials to the channel you listen to, then your out, immediately. I heard about one guy who threatened to quit the XM service and they gave him an extra radio and 3 bucks a month for a year, just so they could keep him. It's also early on, if you influence the DJs maybe you can get the channel you want!
I think it would be in the benefit of each company if they split all the sports chanels. But that kind of agreement is years away.
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