Nuvola Player, an application that is actually a web interface for cloud music services in its own window that provides integration with a Linux desktop, is now at version 2.1 Beta 2.
Nuvola Player provides instant access to the music, shows notifications with currently playing song, it uses the MPRIS interface, has docking capabilities, and it integrates into the Unity launcher.
Nuvola Player 2.1 Beta 2 has received information about format support, access to the Deezer service, support for actions and resident notifications, switches to disable scrobbling for particular services (Last.fm), a few keyboard shortcuts, an option to prefer dark GTK+ theme, and much more.
Remember that this is a development version and it should NOT be installed on production machines. It is intended for testing purposes only.