I think this could be a good gateway drug to music subscription. I've been paying for rdio for years and love the service. Why I chose rdio over spotify? Easy: rdio has a better API and were great to work with. Spotify was the exact opposite (except for @mager, he is always good people.
This is interesting. I'm a huge Rdio fan and have been paying for a while. But there does seem to be a big delta between people who will pay for this or Spotify and people who use the free versions. This might just be enough to get people on the paid bandwagon one small step at a time before being able to get them to completely upgrade.