If you're willing to live without iTunes, Amazon has the broadest video and music libraries, followed by Google, then Microsoft. You can watch or read iTunes-purchased content only on an Apple device, just as you can play videos or music purchased from the Google, Barnes & Noble, or Microsoft media stores only on their respective devices.
However, in addition to playback on the Kindle Fire HD, Amazon lets you play music bought from its store on Android and iOS devices (you need to use its iPhone app on the iPad) via its Cloud Player app. It lets you play rented videos on iOS devices, but not Android, through its Instant Video app. And Amazon lets you read its e-books nearly anywhere using the Kindle app available for most PC and mobile platforms.
Google lets you play music on an iOS device via a Web app, as well as read Google Play e-books on iOS through the native Google Play Books app — but you can't watch Google Play videos on non-Android devices.
Both the iPad Mini's Music app and the Nexus 7's Play Music app (the standard Android player) let you create your own playlists on your tablet, but the Kindle Fire HD's Music app does not. Likewise, the iPad Mini supports podcasts and podcast subscriptions via its Podcast app, but there is no equivalent capability included with the Nexus 7 or Kindle Fire HD; you'll need to get a third-party app instead.
You can use popular video streaming services such as Netflix and Hulu Plus, along with audio streaming services such as Pandora on all the media tablets. Over Wi-Fi, they all played streaming videos and audio smoothly.
The iPad Mini comes in versions for the AT&T, Sprint, and Verizon cellular networks, for $130 more. On the Verizon LTE network in San Francisco, a cellular iPad Mini sometimes struggled to keep up with the video stream — a fact of life on cellular networks from any provider. The Nexus 7 does not come in a cellular version, though $349, 32GB models are planned to support the T-Mobile and Verizon networks. The 7-inch Kindle Fire HD has no cellular model; you have to get the 8.9-inch Kindle Fire, which belongs to a different class of tablets.
For e-books, Amazon has the largest book library of anyone. But that doesn't give the Kindle Fire an advantage, because you can read books purchased from Amazon on your iPad or any other iOS device, Nexus 7 or any other Android device, or for that matter, a Windows 8/RT device.
The content winner. Of the media tablets, the iPad Mini has the broadest options for content sources, not just for iTunes media but for media from Amazon (books, music, and video), Google (books), and B&N (books). Next is Android, which supports media from Amazon (books and music) and B&N (books). It's a no-brainer that the best small tablet for accessing media content is the iPad Mini.
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