Mini-player apps for Mac OS X are quite useful however often they only support one or two media players. This isn’t perfect for people that have collected music over time in different players. In fact switching between players can be quite irritating. The optimal solution could be Simplify. It is a light weight and simple to use desktop controller and shortcut customizer that helps it users control iTunes, Spotify, and Rdio from one interface.
Just like most other mini-players, Simplify shows the current playing track and album cover on your desktop. You have access to most needed controls like play, pause, and skip by clicking on the mini-player. Further Simplify offers a number of customizable shortcuts that work on all three players. As expected it is also possible to choose between a few different sizes and themes, allowing Simplify to blend in nicely with your desktop.
Simplify is a $4.99 download for Mac OS X only.