There's not enough listeners for the number of music services. If your service stumbles, it's easy to move onto something else, so you really only get one or no chances to convince your potential customers.

My experience with Rdio was one of frustration. Their desktop player was buggy and frequently failed to play anything at all. When it did work, I found the consistency of the music catalog to be unreliable. One week they'd have the license to an album I wanted to listen-to, and then they'd lose it, and I couldn't listen to that anymore. I'm not sure what factors were at-play on their end to cause that to happen, but it was a horrible experience for he listener.

I wanted to like Rdio, but they failed at the basics in my experience.