The glass-tastic Xperia Z is subtly stylish rather than flashy, but the power button’s just-so placement and the symmetrical speaker and mic will certainly impress the more discerning gadgeteer. 

Its fiddly – and at first hard to find – covered ports can be a little annoying but it’s all in the name of waterproofing: the Z can spend half an hour submerged and wet-finger-tracking tech means we couldn't get it to slow down much no matter how much we splashed it. Want to clear some emails in the shower? Go for it.

The only thing that's exposed are the two pogo pins on the left-hand side, which work with Sony's DK26 charging dock. 

Available in black, white and purple versions, the angular Xperia Z is the best looking Sony flagship we've seen in quite some time – it's particularly gratifying that the waterproofing and solid build haven't come at the expense of sexy styling. One annoyance: there's no removable battery, like the Nexus 4 and of course cheaper Sony phones like the Xperia J.

Overall this is a very grown-up looking smartphone. So if the white plastic of the Galaxy S3 or the sparkly rear of the Nexus 4 don't do it for you, the discreet Xperia Z really does look like a £500+ handset – especially in black. 

Your eyeballs will love the Z’s 443ppi 1920x1080 ‘Reality Display’. Colours are vibrant without looking alien, contrast is top-notch, and the home screens look crisp – with the exception of the odd disappointingly low-res icons. Viewing angles aren't great, though, so the Z doesn't look as impressive when lying flat on your desk or trying to share a video witha a friend.

Onscreen Android buttons give the display less of a size advantage over the Galaxy S3 (though the home/back/multi-tasking icons of course disappear when watching videos and the like). It's slightly harder to use one-handed, if you're blessed with smaller hands. But super-tough, shatter-proof glass is good news for clumsy folk – our Z's screen has survived a fair few drop 'tests' already.

Text is the biggie – if you read e-books on your smartphone (stop!) or spend your commute catching up on the morning’s news, the jump to full HD will massage your retinas like never before. Text is beautifully rendered on the Xperia Z’s screen, shaming the Galaxy S3’s 720p PenTile display by comparison. For social or news junkies, the choice is a no-brainer. 

Sony reckons its Mobile Bravia Engine 2 software can improve most photos and videos, but since most sites and apps still use low-res images, they won’t benefit from the Xperia Z’s extra pixels. At least not yet.

The Xperia Z’s 5in screen is also perfect for a spot of on-the-fly editing, but be warned: almost all Android photo apps will downsize the 4128x3096 snaps to around half the size before you even get started. When viewing hi-res images, a 1080p screen can display more detail than a 720p screen but even with your nose pressed up to the Xperia Z it’s not as big a difference as you might think. 

There are only a couple of ways to watch 1080p movies on the Xperia Z right now, and that's to film them yourself using the Z's camera or transfer 1080p content from your computer. Make the effort and the results are superb, even though this is 'only' a 5in screen.

It's not night-and-day by any means, but HD content on the Xperia Z is undeniably crisper and more wow-inducing than on the Galaxy S3. It's a shame that right now none of the big movie streaming services are offering 1080p to mobile devices, but we know that Netflix is looking into it and the likes of Sony's own Video Unlimited can't be far behind.

The Sony skin overlaid on the Xperia Z's Android 4.1 Jelly Bean is noticeable without going over the top or bogging the OS down with power-sapping widgets. We'd recommend giving Music Unlimited and Video Unlimited a go – especially the latter – but if you’re really not interested it's quick and easy to get rid of unwanted widgets to make room for the apps and widgets you find most useful. Plus Android 4.2 will land on the Xperia Z 'shortly after launch' which will make it as up to date as Google's own Nexus 4. 

As well as lots of customisation options and an essential settings widget, another nice touch from Sony is that floating ‘Small Apps’ such as a notepad, RSS feed or mini camera float lag-free above any other apps, homescreens and web pages you have open.

It's not quite the split-screen multi-tasking of the Galaxy Note 2 but it's quick, could save you precious seconds and is a clever way of using the big screen.  

The Xperia Z’s 1.5GHz quad-core Snapdragon S4 Pro chip and 2GB of RAM blew theGalaxy S3 out of the water in the benchmarks we ran – though take these upcoming numbers with the usual pinch of salt: benchmarks aren't the best way of judging a smartphone's real world abilities.

On GL Benchmark 2.5 HD, the Xperia Z's score of 3404 frames at 30fps beats the S3's 1685 frames at 15fps. And over on AnTuTu, it's a similar story: theGalaxy S3's score of 12467 looks pretty modest next to the Xperia Z's 20582. 

Chances are you won’t notice much of a performance difference between the Xperia Z and the Galaxy S3 when gaming or browsing using the same browser (say, Chrome) over Wi-Fi.

That's partly because both handsets are very quick indeed but also because we’re yet to see any games or apps which can really put 2013's handsets to the test. Those will come, though, and at that point you'll be rightly chuffed with the Xperia Z's extra grunt. And in the meantime you can enjoy a beautifully smooth, lag-free Android experience.

The Xperia Z sports a 13.1MP rear cam with a ‘Superior Auto’ mode that jumps between 36 scene modes. The camera’s Cyber-Shot style interface is intuitive and there’s a huge range of settings (including focus modes, HDR and image stabilisation) plus plenty of space to see your subject even when zipping through the options on the 5in display. 

The 13.1MP snapper is up there with the best smartphone cams we've used: you'll get natural, bright images from the Xperia Z in daylight with good levels of detail, so much so that you can probably ditch your compact cam. 

That said, we sometimes got slightly better images from the Galaxy S3. For example, although the Xperia Z was seriously quick at jumping to Night mode when we walked into a poorly lit room, the results weren't as sharp as with the S3's low light mode even when you jump into the Xperia Z's ISO and exposure menus.

Video, on the other hand, was more consistent, with clear, bright and smooth 1080p footage – plus there's the option to capture HDR video and the useful trick of taking 1MP snaps as you film.

Along with the usual pairing to headphones and speakers, Sony’s cleverly introduced one-touch NFC mirroring on its new W900A Bravia LCD TVs – tap the Xperia Z to the remote to see all of your vids and pics on a lovely 55in screen. We like. 

The Z’s battery-saving Stamina mode turns off data when the screen is off, boosting standby time by a factor of four, and we found it hardly lost any charge overnight – around 1 per cent, or none at all. When in use it drains just as swiftly as any other flagship – the Z will last five hours of intensive use on full brightness.  

Sony claims 11 hours of talktime for the Xperia Z's beefy 2370 mAh battery and in our regular video rundown test (Wi-Fi and email sync on, video on loop, 50% brightness), the Z managed a respectable time of seven and a half hours. 

We’re looking at an Xperia Z release date of 28 February and pre-orders are open now, so if our niggles with the handset haven’t put you off then get clicking. Of course, the Xperia Z's  price tag isn't half as appealing as the Nexus 4's sub price – but we reckon the bigger and higher-res screen, better camera, waterproofing and sleek design will be well worth the money. 

It’s no mean feat to take on the Galaxy S3 (and Nexus 4) and live to tell the tale but the Xperia Z has stolen our top spot away from Samsung in style. Not only does it make Samsung’s flagship look like a cheap toy with its tempered glass build and thoughtful design details, the Xperia Z also ups the ante with serious specs: a pin-sharp 5in 1080p screen, 4G, a quad-core Snapdragon brain and Jelly Bean 4.2 due just after launch. Sure, you may not feel the full benefit of those stonking figures right now, but you will have a lightning-fast, future-proof beast of a handset.

But it’s not all about the spec wars. Its battery-boosting Stamina mode will make sure the Xperia Z outlasts its rivals, and with a tough pavement-proof screen, intuitive compact-cam style photo controls and a waterproof body, it’s clear that Sony’s really looking out for the everyday gadgeteer. So much so, that the Xperia Z is now our new No.1 smartphone.