I've had plug-n-play Sirius receivers for 3 years now and have really enjoyed the service.  One's mostly used in the house as part of the home stereo and the other travels with me in my car.  Where I live the radio stations stink and I hate listening to commercials on my commute.  Also, I really enjoy the NFL channel for the latest news, interviews, commentary, etc.     
  
My wife's Edge has the Sirius built-in and it's great (she thinks so too).  We'll see how long the service lasts before it shuts off (at least 6 months).   
  
I'd try it and see what you think.  Can't hurt your resale value if you decide to sell one of these years even if you don't use it.....