Well if you ask me, XM, and Sirius have similar programing except for the sports and maybe a premium channel. I do not listen to Stern, so for me the better choice was XM. Besides, XM's monthly subscription is cheaper.
I bet that when Stern is finally on, you will have to pay extra to be able to listen to him. A premium channel. Next thing you know you will be up to $15 or $16 a month. Like i said, for me it was not worth it. The wife is buying me the SkyFi2 for xmas. A lot of nice features.