Several changes have been made to the Xperia Z4 Tablet. None of them are big; a touch here, a tweak there. Add them up though and the result is a tablet so refined that it proves to be a contender for the throne.

Noticeable strides forward have been made with the tablet’s design. The flat, silver border of yesteryear is gone in favour of soft, rounded edging. Aluminium has been used to reinforce the corners and to improve its rigidity. And such a thin tablet needs reinforcing, even if it comes at the expense of seams that advertise where the plastic stops and the metal starts.

Note: The Sony Xperia Z4 Tablet is not yet released in Australia. Our review model was loaned to use by Yatango Shopping, which is currently stocking the 32GB, LTE variant of the tablet for $969.95.

Sony’s representatives claim the Z4 Tablet is the world’s thinnest at 6.1mm. Using plastic for most of the body keeps the weight down. The LTE version being reviewed weighs 394 grams, and that’s 18 per cent less than the equivalent Apple iPad Air 2.

A thinner, lighter tablet is more than just hype; it is the difference between taking emails, the Internet and games with you or leaving them behind. Making a tablet more mobile would be enough for most manufacturers, but this is an Xperia handset, and there are traditions to uphold.

The understated design sources character from the vibrant 10.1-inch screen. Its resolution has increased to 2560x1600 and the brightness is a healthy 500-nits. Every inch of the display packs 298 pixels, and this is superior to any other 10.1-inch Android tablet to date.

The display makes the Android 5.0 world sharper, brighter and more colourful. Things small and big are more enjoyable, whether it is playing a game or sending an email.

History tells us improvements made to the screen come at the expense of battery life. The Z4 Tablet integrates a 6000 milliamp-hour battery and Sony claims it’s enough to loop a video for 17 hours.

We used the tablet to stream video over Netflix and YouTube, to listen to music over Spotify, for social networking, general Internet browsing, emailing and for some light gaming. Brightness was set half way, it was connected to Telstra’s NextG network, both Wi-Fi and Bluetooth were enabled, along with the occasional use of GPS. Good Gear Guide found the Xperia Z4 Tablet would last on average for two days, with our longest result on record being 56 hours.

Looping a video returned results far off Sony’s claimed 17 hour mark. We set the 2K screen’s brightness to max, kept Wi-Fi and Bluetooth enabled and managed to loop a Full HD movie for little more than five and a half hours. This is no 17 hours result, but it is a solid one for a tablet with such a high resolution and bright screen.

Powering the Xperia Z4 Tablet is a Snapdragon 810 processor. It’s an octa-core arrangement that combines a 2GHz quad-core CPU with another clocked at 1.5GHz, and it’s clever enough to switch between the two depending on how much computational power is needed at any one time.

Working with the processor is an Adreno 420 GPU and 3GB of RAM. Internal storage is quite limp at 16 or 32 gigabytes, but the ability to take a 128GB microSD card saves the Z4 Tablet some face.

This top-tier hardware handles the Android 5.0 operating system with ease, gliding from animation to animation, juggling a multitude of tasks and responding to instructions with speed.

A tablet’s lifecycle is less like a smartphone and more like a computer. The guts of the Z4 Tablet — which scored a higher 3DMark test score than the Galaxy S6 Edge at 24,651 — inspire confidence in its ability to plough on in a couple of years time.

True to the Xperia monker is the Z4 Tablet's tough credentials. Its IP65 and 68 ratings certify it for use in freshwater 150 centimetres deep for thirty minutes. Naturally, we put this claim to the test.

Our testing ‘apparatus’ is a tub that can hold water 20 centimetres deep. That’s a long way off 150 centimetres, so we improvised: we kept the Z4 Tablet underwater for longer.

We checked the seals, started the clock and then submerged the tablet. It stayed that way for more than an hour.

The timer on the screen read 1 hour and 5 minutes when we relieved the tablet. Water gushed off its face and droplets lingered on its screen, but the tablet worked without skipping a beat.

A tablet that can tolerate the elements has its perks. It can be used at the kitchen sink, around a pool, in the shower (guilty) or even as shelter from the rain. Don’t expect to use them below the waterline however, as the capacitive screen misconstrues water droplets for touch selections.

Another benefit is the ability to take photos underwater. Sibling Sony smartphones have a dedicated shutter key for this purpose and, although the Z4 Tablet does not, its volume rockers can be assigned the role.

Taken with the rear camera of the Sony Xperia Z4 Tablet

A crop of the photo above at 100 per cent

Not everyone will make use of this feature, but the functionality is there, ready for that sunny day spent swimming.

Photos taken with the cameras rival those taken from Samsung’s Galaxy Tab S and Apple’s iPad Air 2, but even the best cameras in a tablet play second fiddle to those found in smartphones.

More pride has been taken with the front camera as it has increased to 5.1-megapixels, while the rear camera stagnates at 8.1-megapixels. Both of these cameras can record videos in 1080p resolution.

Upgrading the front camera bodes well for the Z4 Tablet. The high resolution camera can take ‘selfie’ photographs fit for the screen of a notebook, plus the improved video recording reaps rewards during video-conferencing calls.

The rear camera is best described as adequate. It has a knack for colour and renders fine details well, only it is let down by a limited dynamic range. Take photos where there are both sunshine and shadows and you’ll have either uniform shades of black, or whites that have had the detail washed out.

Deciding which tablet to buy is dictated by the ecosystem in which all of your other devices — think smartphone, notebook and PC — belong. The margin between the iPad Air 2 and the Xperia Z4 Tablet is so narrow that Apple users won't find it worthwhile jumping across to Android.

People subscribed to Windows or Android interested in a powerful tablet need look no further. No other tablet on the market comes close to the performance, operating system and the sheer breadth of features on offer from Sony's slate.

The first time I saw an Xperia Z4 Tablet was at the Mobile World Congress earlier this year. I called it ‘love at first sight’ — what a bold claim. Now I’m glad to say it was more than a holiday romance.