There's been a lot of back an forth about which service is better and whether the merger is good or bad. Since I have DirecTV at home, I also have XM so I have been able to compare the two.
Sirius has much much better sound quality. XM stretches their bandwidth so tight the music is tinny and hollow. Sirius is much richer. When I pulled out my S50 for some relatives over Christmas, they all remarked that the sound was excellent.
Content is really the big difference here. Clearly the music channels will be consolidated. There's no need for two of the same channels with slightly different programming modulation. The talk channels and sports programming will be the big fight. To me, it makes sense to keep Oprah and dump Martha. Oprah's limited presence and insanely overpriced contract notwithstanding, she's geared more toward radio than Martha. As a artsy crafty person, Martha's more suited to TV. Not to mention she has all the warmth of an Arctic ice core sample.
Howard Stern is a major shareholder and major draw and will surely remain unchanged. Whether he's magnanimous to allow his lame imitators to continue remains to be seen. If I were them, I'd start making nice in a hurry.
How many channels will ultimately be offered?
Who stays and who goes?
What will the price point be?
Which technical platform will stay?
How much infrastructure can be consolidated?
Will programming suffer with lack of competition?
This article addresses some of those points and I agree with most of them.