XM or Sirius Satellite Radio?

I have XM in my FX-35. It is fantastic. The sound quality is far better than in the Pathfinder I had before (which was a wired modulator install).

I'd go for the dealer install. XM is a far superior service IMO (I have both).

This is really not the "big" difference. Both services have dead spots, both have reasonably good reception where ever you are. In general, the antenna you're using is more important than anything else. XM has 4x as many ground repeaters. Sirius appears to have more problems with units in homes, as their satellites are constantly moving with respect to any location on the ground, whereas XM's aren't. Both of XM's satellites cover the entire United States, meaning if you can't get one you can usually get the other. Either service will cutout if you're under an overpass for more than a few seconds, UNLESS there is a nearby terrestrial repeater (XM has 800, Sirius has 200).

Basically, reception is about the same, just with different nuances. More people complain of dropouts with Sirius than with XM (I follow this stuff closely). But either is far better than FM.

The "big" difference is in the music. XM's playlists are huge, Sirius playlists are pretty much like FM. On XM you'll hear stuff you would NEVER hear on Sirius or FM. But again, either is better than FM, and if I couldn't get XM I would definitely have Sirius.

The only reason I would get Sirius is if I thought I was going to be on the road on Sundays and wanted to listen to NFL games. And XM has been really beefing up its content lately, with the addition of NCAA games and starting their own public radio channel. Because XM has 4x as many installations as Sirius, XM is financially able to do a lot more for the listeners than is Sirius.

This is not true. Clear Channel owned a small number of shares (8 million) in XM, but has hedged that interest and has been removed from the Board. Stern had incorrectly stated this on his show, but has subsequently been straightened out about it:

Good info to know. Again, thanks to all for feedback.