If the merger goes through, it could go either way for my tastes. I used to be an XM subscriber (from when they were 2 weeks old), until they eliminated 2 of my 3 favorite channels (Special X, then XM Musiclab). I switched to Sirius, mostly in protest (since I find their music channels to be repetitive) but they never really had equivalents to Special X or Musiclab. Then, a few months ago, they got rid of their channel that was similar to my other favorite XM channel (modern jazz, called Beyond Jazz on XM), leaving me with just one reason to really like Sirius - which is At The Races, a daily horse racing show.
If the merger happens, I expect Beyond Jazz to hang around for at least a couple of years. I would love for the other two channels to return, but I ain’t holding my breath, as both services have clearly shown they like to tweak specialty channels out of existence. Combined, that’ll probably just become more pronounced.