I like sirus much better. It's more like regular radio with live DJ's and all but no commercials. I find XM to more like putting my media player on random play by genre. (I listen to XM via AOL at work sometimes)
Plus I hate the XM names of the channels, they have absolutely no relation to the type of music 90% of the time.
Plus sirius has 3 awesome comedy channels when I don't dfeel like listening to music.
Although XM has baseball, I'd switch football, basketball or hockey for baseball.... but I still get local baseball on AM...
The news and entertainment channels are very similar