I've got to defend XM on this one, keeping in mind that everyone is entitled to their opinion...
First, XM is not just like regular radio. I haven't heard a commercial since Feb 1st. While with FM radio, I most of the time gave up trying to find music I liked and changed to a CD. With XM there are seven music stations and six talk stations that I really like (over 100 channels total). For ex-DJs, it is heaven!
As for the pay per listen argument, unless you 1) don't have satellite TV / cable TV and 2) don't buy music in any form, I'd claim you are already there. Now I'm sure that there are people who truly don't buy any music but I can't imagine there are a lot.
As far as financial information, the latest subscriber figures can be found at:
http://www.xmradio.com/newsroom/screen/pr_2004_04_01a.html
There are a lot of subscribers and XM renegotiated loans last year (as did Sirius) so they should be in good shape for a number of years. XM is also getting ready to launch a third satellite (first was Rock, second was Roll, so I don't know what the third will be called). Sirius has less subscribers than XM.
The sound quality on XM is much better than FM but not as good as CD.
Bottom line is that from the way I look at it, XM is no more like FM than HBO-HD is like the local NBC analog station.
OK, I feel better now...