I'm really hoping they don't mess up XM's current offerings. I would imagine to cut costs that channels with overlapping formats will become simulcasts. I'm hoping the XM channels win out in thoses cases especially the decade channels and comedy channels . The presentation, DJ's, music selection, specialty shows (AT-40, the Top-40 recreations, etc.) are very well done on XM.
Don't be fooled by the Ala Carte thing - what I read of it doesn't make it sound like much a deal. They threw that in since the FCC has long wanted (but not gotten) ala carte on cable TV. Frankly, at $12 a month, you can get an entire year of Sat. radio for what it costs some people per MONTH for cable TV. If there is some ala carte thing at $6 or $8 a month, there isn't enough savings to sacrifice the channel choices.
I'm also wondering - at least half the people I know with Sat. radio have both XM and Sirius. Not sure how wide spread that trend is across the customer base, but I wonder how that will impact the total subscriber count after the merger. It would seem people in that situation will drop one once the merger is done.