i've had xm in my car since january, pionner model hooked into the aux of my clarion with the display mounted between the center courtasy lights. Love xm quality is as good as they say it is, and as for reception its never gone out longer than a few seconds, if your in a long tunnel or out in the sticks somewhere, though it never when out driving backroads from NH to maine
As for commercials your lucky to catch 1 or 2 an hour if u keep it on the same station. Only thing i don't like about the pionneer is its limited to only 8 character display. The skifi is nice since it shows u everything.