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.
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 and audio streaming services such as Pandora on all the media tablets. Over Wi-Fi, they all played the videos and audio smoothly on such services.
On the Verizon LTE network in San Francisco, a full-size cellular iPad sometimes struggled to keep up with the video stream. Expect the same inconsistency on the cellular version of the iPad Mini that ships in mid-November, given the wide variance in LTE throughput and availability on the AT&T, Sprint, and Verizon networks the iPad Mini will support. (The Kindle Fire HD does not come in a cellular version, although a $524, 8.9-inch version of the Kindle Fire HD due Nov. 20 will support AT&T's LTE network. The Nexus 7's 3G -- no, it's not LTE -- cellular versions for AT&T and T-Mobile aren't due to ship until Nov. 13.)
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.
But what about for playing media? Here, the decision is a bit more complex.
Video playback. Many product reviews zero in on the tablet's pixel count, but that's usually a meaningless figure. The quality of the image rarely correlates to total pixels, so my evaluation is based on subjective image quality.