The only good thing about Sirius is how well it is integrated into most infotainment systems. Yes I can stream Google Music but I have to fumble with my phone, which is annoying (and illegal?)
That is slowly changing, though. The Volvo has TuneIn integration, which isn't great, but it does work. You can sync it with your TuneIn account and go through your favorites list etc. to get web radio....at much better than XM/Sirius quality might I add. Its also effectively free since you can tether Bluetooth from your smartphone for the internet access.
However, the system is quite slow and a bit clunky at times.
I think XM etc. have to look for a different business model. With the proliferation of mobile broadband (first on phones, now in cars!) its just not necessary to have Sat radio any more. They simply do not have the bandwidth to offer enough value and they have to launch a satellite to get this stuff working. By comparison I could probably host a web radio station off my laptop.
New technology once again makes an old business models redundant.