We have Sirus and really enjoy it. So far commercials haven't invaded the regular channels.
The best part is the sports coverage. We can tune in just about any football game you want. NASCAR works, too, cause here in LA, we don't get NASCAR on the local radio.
I listen to Margaritaville pretty much all the time

and the SQ isn't that bad. Then again, I am using the dedicate Alpine compatible reciever that plugs into the AINet port on my CDA7998. I have noticed a loss of highs, tho...
Margaritaville doesn't have commercials, per se. They have breaks, and will announce contests, concerts, schedules or new releases. It's not an ad in the direct sense of the word.
As for the merger... I hope they remove the dupes... We don't need two 80s channels, for example.
As it stands, I think there are enough channels... they don't need to start adding a station for every interest and fettish... I mean, do we really need to have a station for black-German-cross-dressing-women-with-a-limp? I don't think so, but that's the direction it's heading in.
As for SQ in general, it's fair, but it isn't great. The only thing that saves it is my system and the way I input the signal. You all are right, most consumers wouldn't know good sound if it kicked them in the ass, so they will continue to get away with too many marginal channels and poor SQ.
However, I can notice a huge difference when I listen to a CD... and if any of you are ever in the LA area, tune in Jack FM, 93.1. It isn't for the selection (a bit spastic) but for the signal strength and clarity.