As a society we're in thrall to the thrill of the new.

We expect our phones to arrive touting amazing new features and when they don't - as is the case with the Sony Xperia Z3+ - our natural reaction is to be disappointed.

In some ways that's a little unfair. After all, the Z3 was a mighty fine phone that really didn't need much improving. Maybe giving it a bigger battery, slightly new design and new processor was all Sony needed to do?

Problem is, this year's already welcomed a couple of fantastic new phones in the form of the Samsung Galaxy S6 and S6 Edge and the LG G4. And in that company, a minor upgrade was always going to be a hard sell.

Return of the box

If you are looking for something truly different about the Xperia Z3+ you won't find it in its design.

The Z3+ is instead best described as a further refinement of the series’ classic style. It’s skinny, but has a boxy, rectangular shape that stops it from feeling as wafer-thin as it is.

Compared to the Xperia Z3 it has lost a bit of bulk in every direction, but the notable changes aren’t about millimetre-measuring. Sony has really cut the Sony Xperia Z3+ style back, making it as pure and simple as possible. I got to compare it side-by-side with the Xperia Z2, and the Z3+ really makes that older phone look a bit of a mess.

There are no longer any weird dock ports, and the sides are simple, smooth curves that only have interruptions when they’re strictly needed. And the best bit is that while the Sony Xperia Z3+ is still water resistant, it no longer needs any flaps other than the one that stoppers the SIM/microSD slot. The one you’ll never have to move, in other words.

The loss of those flaps is because the Z3+ has treated microUSB and headphone jack sockets that don’t let in water. This is what you want: waterproofing without the inconvenience. It’s still IP65/68 certified too, meaning it can be dunked in water for 30 minutes, no problem.

Lots of people seem to be a bit disappointed with the Sony Xperia Z3+’s lack of jazz-hands extras, but I find its design to be solid. The edges are still a mite sharp, but you get used to that after about five minutes.

The sides are also incredibly shiny, which risks them looking a bit like glossy plastic, but be assured that they're actually coated metal. There's Gorilla Glass on the front and back and although the corner bits are plastic, that's likely because plastic absorbs shock more readily. This is a “whatever happens, don’t let the glass smash” measure.

Overall, it's the best looking phone in the Z series so far.

Global hypercolour

As with its design, the Xperia Z3+'s screen has undergone a few changes without exactly being reinvented.

To that end, it still has the exact same specs as those of the Z3: it's a 5.2in LCD display of 1920 x 1080 resolution. Like the HTC One M9, Sony hasn’t made the leap to QHD. But with 424 pixels packed into each inch of screen, it’s still very sharp.

What really defines the display on the Xperia Z3+ though is colour. 

This screen is incredibly vivid and though the white balance tends to the blue end of the spectrum to start with, you can easily warm things up by tweaking the white balance controls in the settings menu.

It's a shame you can't do the same for colour saturation - it seemingly uses the same standards as Willy Wonka’s chocolate factory. Again, careful calibration keeps it looking good (if not by any means accurate), but we'd prefer the option of a mode that would do it for us with one click.

Still, overall Sony has absolutely achieved the lively and punchy look it's going for.

Cool, calm and colourful

The colourful screen works pretty well with the custom Sony interface, which embraces colour wholesale while also looking more grown-up than some other UIs. It’s better-looking than LG’s and a bit more consistent than Samsung’s.

It’s simple too. The Sony Xperia Z3+ doesn’t jam in extra home screens or try to pack the notifications drop-down with more controls than an airplane cockpit. It just looks a bit different while also letting you organise the apps menu more than you're able to on standard Android; you can add folders and choose how the apps arrange themselves.

Under the Sony UI you get Android Lollipop 5.0.2, a pretty recent version of the system.

Performance is just about perfect too. As usual these days, Sony’s interface doesn’t drag the system down and make it feel sluggish. Of course, there’d be no excuse for lag given the Sony Xperia Z3+’s insides. It has the Snapdragon 810 CPU with 3GB RAM, and scores 3374 in Geekbench 3: a good total, if not the best I’ve seen from this CPU. The phone also seems to use quite severe throttling when the phone heats up (an issue about which you'll read plenty more further down).

Games run perfectly, even those GPU-roasting ones, and with 32GB storage on-board there’s enough space for most people to get on with, without buying an SD card. It’s all sounding pretty dandy.

Miami heat

But there’s a problem: heat. The Sony Xperia Z3+ has a serious issue with overheating, and it’s something Sony has acknowledged and is working on improving later this year.

Gaming sets it off a bit, but there were much more obvious issues when using the camera. When shooting 4K video or using the AR mode, you will be warned the phone is heating up, and the app will close if it carries on doing so.

A couple of times during testing this happened, but there were others where I was able to get through several minutes of 4K shooting with no issue. What I found more annoying was that when the Xperia Z3+ heats up, it starts doing stuff behind the scenes to try and keep the heat down. So on a sunny day you might find the screen goes so dim you can barely see what’s going on, even after turning off auto brightness.

Part of this issue seems to be down to the Z3+ not spreading its heat out very well. It mostly sticks to the top of the phone, with one spot to the side that gets “oh crikey is it going to start melting?” hot at some points.

How long can it last?

When a phone gets hot you start to assume it’s going to have rubbish battery life. After all, that heat it basically wasted energy. However, the Sony Xperia Z3+ has decent stamina.

It comfortably tops the LG G4 and HTC One M9, generally leaving you with around 30-40% charge left by bedtime to sail you into the second day with no worries. In fact, we'd say that along with the Samsung Galaxy S6, the Z3+ seems to have among the best staying power of all the big-name 2015 flagships.

However, if anything it should be better. Battery life does seem a fair bit worse than on the Xperia Z3, especially in our looped video test. It lasted for 10 hours, where the last Z-series phone made it into the teens of hours.

Still, at least its 2930mAh unit outdoes the LG G4. The LG G4’s 3000Ah battery is bigger, but doesn’t last for as long. The numbers certainly aren’t everything.

Megapixel monster

The number may not mean everything on battery life, but as usual Sony is out to top everyone with its megapixel count.

The Sony Xperia Z3+ has a 20.7-megapixel sensor, just as the Z3 did. I had expected Sony to give the phone a bump up from the IMX220 to the IMX230 sensor, but Sony’s specs suggest it has stuck with the older version because the Sony Xperia Z3+ has a 1/2.3in sensor and the IMX230 is a 1/2.4in chip.

Enough of the geek speak, though. What we get here is a 20-megapixel camera that, 95% of the time, takes 8-megapixel images, using the extra sensor info to make those 8MP images that bit cleaner and more accurate.

The Sony Xperia Z3+ has a camera of strengths and weaknesses. Its Superior Auto mode, the default one, is very smart and can adapt to any situation. And we mean any situation.

Even though the Sony Xperia Z3+ does not have optical image stabilisation, it is able to do more with extreme low-light situations than any other flagship thanks to a special ‘Low Light’ mode. This supercharges what light there is to make scenes even clearer than they appear to the eye a lot of the time.

The results often don’t look that natural and are predictably very low on detail, but it’s a real masterclass in smartphone camera processing.

It deals with the lows well, but the Sony Xperia Z3+ doesn’t hit the high points reached by the LG G4 and Samsung Galaxy S6. You can only take 20-megapixel shots in the Manual mode, and the results don’t look as clean as those of its LG and Samsung arch-enemies.

HDR performance is nowhere near as good either. Shots often lack that extra bit of extra pop, and colour saturation suffers when there are strong light sources in or just outside of the scene.

I also think the Sony Xperia Z3+ needs a middle-ground between its Superior Auto mode and the Manual mode, which doesn’t even let you pick the focus point until you change one of the settings in the menu. It ain’t that friendly. The Z3+ camera is a thing of extremes in this respect, whereas LG, Samsung and even Apple hit a middle ground that gives you more of a sense of control while still handling 98% of the leg work.

Where Sony tries to make up for this not-quite-top performance is with loads of bonus modes. This has been its tactic for years now, but Sony has still managed to add a few new extras here.

The main one is AR. This pastes 3D animal faces on to people in classic “it’ll entertain the kids” fashion. As mentioned earlier, this is one of the things that really makes the phone start to heat up.

The other is 4K video. The Sony Xperia Z3+ can shoot the super-sharp video today’s kids are going crazy for. But actually using the mode on a bright day is a right pain, as the phone dims its display to try to make sure it doesn’t heat up too quickly. This effect doesn’t stop as soon as you leave the camera, either. Take the phone out on a sunny day and push it for a bit and outdoors visibility of the screen will be killed before too long.

Clearly, a bit more work is needed. But at least we know Sony is on the case.

There are plenty of other fun AR-based modes too, and more filters than you’ll know what to do with. You can even download extra third-party ones from within the app.

But after the buzz of turning your face into a gorilla mask has died down, you’d probably be better off with an LG G4 or Samsung Galaxy S6. It’s a bit of a kicker given that both phones actually use Sony sensors.

Back when Sony was the company pushing skinny phones more than just about anyone else, it was easy to blame issues such as overheating on the thin-ness of the Xperia phones. But now that just about everyone is making phones skirting the 6-7mm mark, that excuse no longer works.

The Sony Xperia Z3+ speaker doesn't impress too much either, and since the Alcatel OneTouch Idol 3 showed us how hefty drivers can sound in a phone this skinny (and at half the price), it’s a bit disappointing. They’re not terrible, but just don’t have the extra bit of mid-range bulk we’re starting to expect from higher-end phones.

They don’t get close to matching the HTC One M9’s BoomSound speakers, for example. At max volume they also cause the back glass to vibrate quite a bit, which feels odd when you’re holding the phone to play a game or watch a movie.

One strange side-effect of this is that if you put the Sony Xperia Z3+ down on a flat, slightly resonant surface such as a table, it’ll actually amplify the sound, adding the beefiness that the speaker itself is missing. So it can sound kinda good, just not on its own.

Sony Xperia Z3+ verdict

Where the LG G4 and Samsung Galaxy S6 were bold steps forward for their respective series, the Sony Xperia Z3+ is more like the HTC One M9 in its familiarity.

Changes to the outer design are welcome, but inside there’s nothing you’d call radical. That wouldn't in itself be a problem if all of the refinements, however small, were positive ones.

However the big change, upgrading to a Snapdragon 810 CPU, causes the Sony Xperia Z3+’s biggest problem: overheating. Tales of it crashing out of apps every five minutes to avoid bursting into a ball of flame are exaggerated. But the way it dims the screen to compensate is a downer.

In not levelling-up the camera, the photo side also falls behind the competition from Samsung and LG, and while the battery is still very good, it's not quite as good as its own predecessor the Z3.

Still, that battery life remains class-leading, while its classy UI and a super-bold larger-than-life screen deserve to win it a healthy crop of fans. Maybe just not quite as big a crop as it would without those flaws.

Tech Specs 
Android Lollipop with custom UI
5in, 1,920 x 1080, Triluminous LCD display
Octa-core Snapdragon 810 CPU
32GB (with microSD)
20.7MP, f/2 lens, single-LED flash, 5MP front
Wi-Fi, NFC, Bluetooth 4.1
146 x 72 x 6.9 mm
Stuff says... 

Sony Xperia Z3+ review

A solid and likeable phone with great battery life but overheating issues keep it from the top of the pile
Good Stuff 
Super-punchy screen
Purer design
Good performance
Bad Stuff 
Prone to overheating
Worse battery life than Z3
No particularly exciting upgrades