Sony claims eight hours of web browsing and 9.8 hours of video playback, and it gets close to these targets. When playing an HD video on loop with Wi-Fi left on, it lasted a creditable eight hours, 23 minutes. Switch off Wi-Fi and use more power saving measures and you could stretch that out to nine hours or more.
Cameras are a good deal less important on a tablet than battery life, so we won't spend much time on them. Indeed, clearly Sony hasn't either. An 8-megapixel backlit Exmor R sensor camera on the rear and 2.2-megapixel front-facing camera sound impressive on paper, but the reality is grainy, unflattering images in anything but perfect light. They're adequate for basic use, but not much else.
It's worth knowing Sony sells a 3G version of the Sony Xperia Tablet Z for £499, £100 more than the non-3G equivalent. It comes in 16GB and 32GB capacities, too, which is ample given there's 11GB free on the 16GB version and a microSD card slot as well.
The Sony Xperia Tablet Z is among the most capable 10-inch Android tablets around, that much is certain. Even so, we can't recommend it without some reservations.
The fact it doesn't run the latest version of Android is irksome, but its biggest problem is it feels wedged between two arguably superior options.
If you don't have a fundamental aversion to Apple, it's hard to look past the iPad 4 at this price and size. It has a better screen, better apps and is more likely to be supported with regular software updates. The Nexus 10, meanwhile, while slower, is £80 cheaper and has a better screen. And all this before you consider the likes of the Asus Transformer Pad Inifinity or cheaper Asus Transformer Pad 300 and its nifty keyboard dock and tablet combo.
None are water resistant, of course, but how often do you really think that will be useful? The Sony's faster processor and lightness are better arguments in its favour, at least they will be for the majority.
The Sony Xperia Tablet Z is a very good tablet - there's no doubting that. It's fast, has a good screen and is very thin and light. But it does no single thing appreciably better than its immediate rivals, and its unique features fall a little flat.