Well, XM's satellite is so low on the horizon that these damn mountains get in the way--so, not so good.
---I commute from Altoona to Clearfield three days a week and XM's reception is great. I have not had problems with the mountains, only some overhanging trees on a spot of the highway between Sandy Ridge and Bald Eagle. I wish the signal on my cell phone was as good. The only local FM station I could listen to the whole trip was WPSU--but, I had the change the frequency three times. And, no I couldn't receive the 50kw stations---WFGY & WGMR--for the whole commute either.
You mean from a competitive angle? Shoot, XM & Sirius have so few subscribers--relatively speaking--that they're not a real factor. In 20 years? Yeah, maybe.
---Granted, subscriber numbers and market penetration aren't where XM and Sirius would like to be at this point of the business cycle, but both are relatively new services and are early in the developmental curve (compare the cycle to the emergence of cable TV). And, if they're not a "real factor," why is the NAB so concerned with the merger of the two services? I know the NAB is trying to ward off a competitor and is protecting the "localism" of AM & FM. But, IMO AM & FM lost its' localism focus years ago; from widespread voice tracking, to the use of repeaters and morning shows originating from far off cities, and the lack of funding for local news departments.
If you're into different genres of music, seek emerging artist and deep playlists within a genre--satellite has that (XM more than Sirius). There isn't a classic rock station around that compares with XM40 "Deep Tracks." Or, an oldies channel that presents the genre as well as XM6 "60's on 6." As well as, Fox News, comedy, the MLB, NFL, NBA, etc---you can read the ads for each service to see what's offered.
And, if you're happy with the music and service(s) of AM/FM---stick with it.
And, I know terrestial radio could give a crap about what I think---being outside of the age demos they're trying to reach---so, I know already what to do with my opinion.