Amazon has now officially launched its music streaming service we previously reported on. Along with a number of other benefits, Amazon Prime members now have access to unlimited, ad-free music streaming with the new Prime Music

At no additional cost to the normal membership fee, Amazon says there are over 1 million songs to stream for free. While you'll find artists like Daft Punk, P!nk, Bruno Mars, Blake Shelton, The Lumineers, Bruce Springsteen and Madonna in the catalogue, some are already criticizing the service for its limited selection of songs and awkward interface.

Amazon is reported to have gone through 6 months or more of negotiations with the music industry in order to lock down Prime music, but it appears the service is currently missing many of the latest hits from the most popular artists. We initially were lead to believe that Amazon's streaming service would only be able to offer tracks from albums that were at least 6 months old, and to some degree that appears to be true. 

A report from the New York Times says that Amazon could not make a deal with Universal Music Group, the world's largest music label, and will in turn not be able to offer artists like Lady Gaga, Kanye West and many others.

On top of that, the means in which the user can search for and then select a song is quite cumbersome and much less immediate that other services like Spotify. Some have suggested this could simply be due to Amazon needing a UI refresh to accommodate the new service, but could also be in order to have its much more thorough music download options as present as possible.

Amazon has also updated, relaunched and renamed its free Amazon Cloud Player iOS app to Amazon Music. The mobile app will now have full support for the new Prime Music streaming service, allowing members to bring the catalogue of music anywhere they go.

While the Prime Music service isn't likely to cause much of a problem for Spotify and its 20 million songs, it is a nice add-on for those who were already paying for Prime membership regardless of the limited catalogue. Amazon previously said it has 20 million Prime subscribers and 244 million "active customer accounts," so there is some potential for the service to pick up, especially if the company can manage to expand its catalogue of songs.