Sirius isn't free, you pretty much have to buy the hardware too.
Also, 90% of their stations are outright garbage and far less personalized than Pandora.
At the same time, Pandora is ridiculous because it's treated more like a radio stream and less acknowledging basic functionality like "I want to play a song again" or "I want to restart the same song". Spotify is equally garbage in this regards as you are limited on the number of streams and the selection is limited. Google music is the next closest thing at $8/mo, but in reality it's no better as well.
Until you have a streaming service that doesn't have to resort to covers to play certain songs just because the big bad publishers think their music is so magically valuable (it isn't), we're going to be stuck with garbage solutions like this.
What isn't mentioned about every music streaming solution? None of them pay the artist *anything*, because this assumes artists actually get their tenth of a cent per stream. It's unlikely, because that's probably split 20/80 with their publisher, assuming they even get the money and that a publisher isn't somehow taking all the money from the artist who doesn't even work for them.