Sony's just busted out its entry into the dreaded phablet market, and there's no getting around it: Sony's Xperia Z Ultra is massive -- bigger than even the Samsung Galaxy Mega 6.3 -- but it's an absolute power-house, and thin too.

In the hand, it feels like a tablet; a really thin tablet at that, but a tablet nonetheless. At 6.44-inches, it's only marginally off the mainstay breed of 7-inch tablets like the Nexus 7, but thankfully its bezel is so small it's significantly more compact, meaning you can pretty easily one-hand it like a phone. Design-wise, it's like an Xperia Z crossed with a Lumia 925. Everything is the same as the Xperia Z -- glass front and back with a similar bezel -- it's just that the plastic edging has been replaced by a metal band, like the Lumia 925. It's attractive, and feels reassuringly solid in the hand, which is good given you're going to want to grip onto this thing pretty tight.

It's running the lightning-fast new Qualcomm Snapdragon 800 quad-core chip clocked at a frightening 2.2GHz backed by 2GB of RAM. That means it's liquid smooth and fast, even on pre-production units. The screen meanwhile is large, vivid and sharp. Although technically not as sharp as the Xperia Z, Galaxy S4 or HTC One, due to being 1080p but stretched over 6.44 inches instead of 4.7 or 5, it wasn't noticeable in my quick play. In fact, the screen popped well, with vibrant colours and crisp video.

Unlike most other phablets, the Ultra Z doesn't ship with a stylus in the box, and there's no hole for one on the device anywhere. The clever bit is that you don't actually need a dedicated stylus for handwriting recognition etc -- you can just use a common-a-garden pen or pencil right on the screen. Sony's implemented a new touchscreen tech, that while still capacitive, can detect things as small as a pen nib, but whether you'd want to literally write on your screen is another matter. It's covered in scratch resistant glass, but in our testing we've found Sony's Gorilla Glass equivalent less than scratchproof on the Xperia Z and Tablet Z.

Sony Mobile has also nabbed the Triluminos tech that its TV division shoved into its latest W9 series of Bravia TVs, which was quite a leap over the previous generation technology in both colour saturation and balance. It's difficult to truly tell in a brief hands-on with the device, but it seems the same can be said for the Z Ultra. I'll wait till we get one in the office before I pass judgement, but let's just say things look promising when compared with the Xperia Z.

At 6.5mm thick, you can actually fit this thing in your pocket, just. But you won't be able to, you know, move with it in there. Sony's pitching it as passport size, but it's longer than a passport and it won't take kindly to you sitting on it. Of course you can shove the Ultra in your back pocket, but it sticks out the top, making you a glowing mugging target walking around on the street. Needless to say, you'll need a bag to carry this monster around.

Sony's bumped the phablet's waterproof rating up to IP58 this time round, which apparently covers submersion, rather than just immersion (IP57). In reality, it basically means you don't need to worry at all about water around the Ultra. You can sink it in up to 1.5m of water, which is quite deep for a non-specialist gadget, while Sony's made improvements to all the seals keeping out the elements around various ports, slots and holes. The result is that the headphones port doesn't need a door, unlike the Xperia Z, and is permanently exposed, which might not sound like a lot, but in practical use terms it's a huge boon.

Sony could be onto a winner here considering the trend for bigger is better with the Galaxy Note series and other phablet entries, but the Z Ultra is so big it's not going to be practical for most people. Unless you're willing to carry around a manbag, or wield a handbag normally, you're just not going to be able to fit a 6.44-inch tablet-cum-phone in your pocket. Likewise you might also feel a bit stupid talking to something that big mounted on the side of your face, but we'll gloss over that for now.