Activation of both units was relatively simple: Plug the units into a power source, attach speakers and the antenna unit (which is also small, with the actual antenna being about the size of a silver dollar), call the company to activate the unit (this only takes a couple of minutes), and one will immediately begin receiving a signal.
The tricky part is the placement of the antenna for optimum signal strength. When setting up the Sirius unit I first tried placing the antenna next to a window (this is recommended) on the southwest side of my second-floor apartment. Although a signal was found, it turned out to be weak. A window facing the southeast eventually turned out to be preferable. The XM device achieved similar results. In both cases the length of the wire leading from the antenna to the receiver was generous, better than 20 feet. Signal quality for both units was generally excellent, though heavy rain could interfere with signal quality to some degree.
XM also provided a very stylish PlayDock PD200 boombox-type docking station ($199.99) manufactured by Cambridge Soundworks, which provided significantly better sound quality than the Altec Lansing computer speakers I had previously been using, with the unit's subwoofer providing vastly improved bass response.
Opinions on which company provides better sound quality seem to vary widely. My experience was that the XM signal seemed to sound marginally better, but one's experience could well be different depending on location, antenna placement and local topography, among other factors. And, in fact, I have heard testimonials from other users that Sirius' sound quality is better to their ears.
Which is right for you? It's a matter of taste. Both companies offer about the same number of channels, so the deciding factors probably lie in the details. If you're a fan of shock jocks, XM now carries Opie and Anthony, and Sirius will be carrying Howard Stern beginning in 2006. If you 're a sports fan, Sirius is currently carrying all NFL games, and XM will begin offering Major League Baseball on 16 channels beginning in the 2005 season. XM charges a low of $9.99 per month, while Sirius is $12.95.
Fortunately, both companies offer free 72-hour Internet subscriptions through their respective websites so you can find out for yourself which one fits you best. And who knows? Perhaps you'll like them both.