Let me also say that quality varies a lot from station to station and that is understandable. Sirius advertises this fact saying that they allocate bandwidth where it's most needed. Pop stations that are playing recent music are clearly given the highest bandwidth. "Oldies" type music has a lot less bandwidth. Talk radio sounds like bad AM radio or even short wave!
My original comments were about the best quality stations (like Hits1). Other stations can be more disappointing to varying degrees. Talk radio is just shameful (IMO) although it's just talk so in theory it shouldn't matter. This morning I compared the BBC news on my local FM NPR station and the Sirius BBC and the difference was huge. Again, this is talk so it's not a big deal, but I truely felt like I was listening to short wave radio on the Sirius side.