HOW TO MAKE THE DECISION BETWEEN XM AND SIRIUS SATELLITE RADIO

The other day I was listening to XM Radio on the "80's on 8" station and the announcer stated from planet Earth. I laughed because what he was really saying is that all radio stations provide you a call indication and then they say, what city they are from, however XM radio is a terrestrial satellite radio station and it beams at signal to whoever