You can initiate a live search by simply beginning to type while the app is in the foreground, which is pretty cool, but it shows the same results regardless of which view you're in at the time. In other words, it displays (in order) artists, albums, and songs, regardless of how you were viewing you music. And it cuts off after an arbitrary number of items. Select a result to drill down into it in the main interface.
One problem I've had with Cloud Player is that I've amassed many duplicates, thanks to running the uploader app on multiple Macs and it not being smart enough to know those songs were already uploaded. I was hoping that the desktop app would make it easier to clean up my cloud library. Alas, there's no feature to locate dupes, but it is somewhat easier to select and delete multiple items in the desktop app.
Unfortunately, uploading new content to your account still requires the horrendous AIR uploader app. In the desktop app you select File > Import Music To Cloud Library, click OK to be taken to your Amazon account, click the Import this music button to launch the AIR application, and then pick and upload your music. And that's when it works. Now every time I try to upload new music, I'm forced to redownload the uploader app.
One nice feature is the integration of Amazon's MP3 store into the app. Click the Store button in the upper right corner and the UI shifts to one in which you can browse and buy music. One problem I noticed, though, was that it doesn't indicate whether or not you've purchased something previously. For example, I bought Mozart: Complete Symphonies (The VoxBox Edition) but wouldn't know it from looking. Visiting the album page on Amazon.com shows me a banner indicating I've already bought it.
Although I'm glad to see Amazon bring its desktop app to the Mac, in many ways it's less functional and more difficult to use than the Web-based interface. And failing to integrate an uploader into the app is just inexcusable.
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