MOG Desktop is the native app that will allow the company to check off the 'native client' box that Rdio, Pandora, Spotify, Zune, and Rhapsody have been able to until now. While it's essentially a rebadge of the website's HTML5 player (and accompanying Chrome Webstore offering), the OS X counterpart includes AirPlay — a feature the aforementioned competition currently lacks. It will work with your Mac's media keys, but won't work offline since there's still no caching. Regardless, this appears to be one of the first non-Apple apps utilizing AirPlay on OS X proper, so hopefully that means an influx of AirPlay-ready apps on the way.
Source: Mac App Store, via Gizmodo