It will be interesting to see how Apple Music affects them. If you listen to a lot of new music, the cost of switching music services is pretty trivial (moving from Rhapsody to Rdio to Spotify has been a minimal hassle for me), and being able to call up any album with Siri is a powerful advantage. Fair or not, this is why Apple could report a vast advantage in map requests over the superior Google Maps.

I like Spotify a lot, but they look to have a weaker defensive position than Dropbox or Netflix to me. With minimal switching costs (search is the main interface even if you build up something of a "library") and undifferentiated content, it's really a commodity service.