bb, I have an XM Myfi, bought XM for MLB season(as Sirius NFL,NBA, NHL doesn't appeal to me due to being home on weekends and night), it is excellent, and though I paid $250(usually sell for $300)..they are at $150 Christmas prices everywhere right now..time to buy!
XM has great sports radio, music, and has an 24 hour MLB station called MLB-Homeplate..with Kennedy, Dibble, Steiner,etc..
You'll love it, the MYFI comes with all kinds of gadgetry, it can be used on body, in car, at home, and a subscription gets you internet use also.
http://www.xmradio.com/myfi/index.jsp