I live in a very rural area, West of the appalachian mountians, High mountains, cliffs and trees.

I have owned both, at the average price range of $100.00 or so.

Not to knock XM Radios but in the area I live in. The XM radio was always loosing signal do to lack of signal reception.

With Sirius radio I still lose signal reception,  But it picks up the signal where  the XM Radio would not.  So before buying ask around with others in your area how good of a reception they get.

If you live in a City, or open plains you shouldn't have any trouble recieving with either system.