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Asus Zenfone 4 (2017) Review: Serious OnePlus 5 rival?

The Good

  • Nice design
  • Feature packed
  • Flexible camera tech
  • Long battery life

The Bad

  • Unintuitive software
  • Underpowered

The Zenfone 4 is one of Asus’ first smartphones to make it to the UK in some time, besides the super-expensive Zenfone AR that is. Boasting a feature-packed dual-lens camera and the nifty ZenUI OS, the Zenfone 4 is an enticing mid-range mobile and possible alternative to the OnePlus 5.

At £450, Asus’ new Zenfone 4 is placing itself as a direct rival to the latest OnePlus handset. They share the same UK asking price, as well as many similar features; both of these mobiles offer a dual-lens camera and a Full HD 5.5-inch display, for instance.

It’s a brave move to go up against the OnePlus 5, which sports some very strong specs for a very reasonable cost. Of course, the Honor 9 already managed to impress us just as much in pretty much every respect, even undercutting OnePlus with a £380 price tag. Great stuff, considering the excellent camera tech, powerful processor and solid specs.

So, how does the Zenfone 4 fare, in a market where few people have even heard of an Asus smartphone let alone touched one? Here’s my full review after using the Zenfone as my full-time phone for a week.

Asus Zenfone 4 Review: Design

Asus has had a fair bit of practice by now when it comes to smartphone design, so the Zenfone 4 certainly doesn’t disappoint. While the aesthetics aren’t particularly stand-out, this device sports a smart and attractive finish that suits the mid-tier asking price.

That aluminium unibody frame is coated in glass around back, for a shiny appearance that mimics the front. That glossy rear does a pretty good job of masking fingerprints and other marks; at least, in the midnight black model, which we tested. You can also grab the Zenfone 4 in white here in the UK.

Of course, one drawback of that smooth surfacing is the slippery grip. Place the handset on a slightly inclined surface and it will inevitably begin a steady slide, while clutching the phone requires a seriously sturdy grip (and preferably non-sweaty palms). Thankfully the Zenfone 4 so far seems more sturdy than the Honor 9. No cracks or scratches have appeared on our review model, although we have seen scratches on some other reviewers’ handsets.

One design feature that we do enjoy is the circular patterns that shine across the rear surface when the Zenfone 4 catches the light. This is a funky effect that Asus has used countless times before on its devices and it works well here.

You don’t get a water resistant finish, although the handset seems to cope just fine with rain and splashes.

What works?

The Zenfone 4 appears to be hardy enough to survive everyday life, including the odd bit of rough treatment such as being tossed into a bag. That design is rather attractive too, if not particularly stand-out, with camera lenses that lie flush to the surface.

What doesn’t?

The glass surfacing makes for a slippery grip, while there’s no water resistance to speak of.

Asus Zenfone 4 Review: Screen & Media

Media fans have plenty of reason to invest in the Zenfone 4.

For one, the 5.5-inch IPS screen is as strong as any of the competition, certainly at this price point. You get Full HD visuals, so your photos and videos will look sharp despite the large panel size, while the brightness levels are strong enough for easy viewing in bright daylight.

Colours are pleasing to the eye, without proving unnaturally vibrant, although you can fiddle around with hues and saturation levels in the Zenfone’s display settings if you fancy it. There’s even a ‘vivid’ setting, if you want your visuals to really pop from the screen. On top of that you have a blue light filter feature, which produces warm, easy-on-the-eye visuals for more comfortable night viewing. Sadly there’s no kind of timer to automatically activate this in the evenings, which means you’ll need to manually turn it on every night instead.

However, we did find that the screen was near impossible to see when wearing sunglasses; not a problem that should trouble us Brits much, at least.

Music fans haven’t been ignored either. You get full support for Hi-Res audio playback, for enjoying top-quality tracks, while the Zenfone 4 also offers Bluetooth 5 connectivity. This means you can hook up to two separate speakers or headphones at the same time, handy when travelling with a partner. Asus has also served up some manual audio controls in the form of the AudioWizard, which can tweak the output based on your type of headphones and plenty more besides.

You get 64GB of storage on board the handset, of which just over 50GB can be used for your apps, media and everything else. You can also plug in a microSD memory card (in the second SIM card slot), to expand by up to 2TB. That’s something not offered by the OnePlus 5.

What works?

The spacious display is sharp, bright and offers full manual control over the colour output. You also get Hi-Res audio support, plus expandable storage for carrying a massive media collection.

What doesn’t?

We’d have liked a schedule function for the blue light filter mode, but besides that, we can’t really argue.

Asus Zenfone 4 Review: Features and OS

Android Nougat is overlaid with Asus’ own ZenUI software, which significantly changes the look and feel of Google’s OS while adding a fair bit of bonus functionality.

While the core structure of Android remains intact, Asus has replaced the fonts and icons to give the operating system a unique appearance. You can edit most aspects of the UI design by flicking a finger up your desktops, which opens the ‘manage home’ menu. This gives access to wallpapers and themes, as well as the ability to tweak the grid layout, scroll effects, font sizes and colours, folder sizes and so on.

The scope of the Zenfone 4’s customisation is impressive, matched by few other phones we’ve recently tested. Hell, you can even share your ZenUI setup with other Zenfone owners, if you like.

As well as standard Android features such as split-screen mode, the Zenfone 4 also serves up plenty of extra functionality; although a lot of it is buried away in the settings menus.

Elderly users or anyone who needs an extra helping hand can activate the nifty Easy Mode, which delivers a simplified interface with large, clear icons for the most-needed functions. The ZenUI Safeguard feature is also a worthy addition, offering a quick SOS alert to be sent to preferred contacts, as well as full location reporting. Of course, the Zenfone 4 isn’t an obvious choice for this user base all the same; we’d point to Doro’s handsets instead.

Meanwhile parents will appreciate the awesome Kids Mode, which can prevent your nippers from accessing certain phone features when they’re bingeing on Peppa Pig. Definitely a good thing.

Asus’ Customised Settings also delivers quite a few extra tools. You can sign in with two different accounts on the likes of Facebook, for instance, or stream your mobile gaming session straight to Twitch. Frankly, there’s so much to cover that we’ll end it there. Needless to say, the Zenfone 4 offers a broad range of bonus modes, most of which will be useful to specific user bases.

However, while you’ll (eventually) find a fair few decent features tucked away inside of ZenUI, the software is quite badly laid out and basically unintuitive. You’ll have to really go hunting to find some of the coolest additions, which makes this phone better suited to technically confident users.

We also noticed a few little bugs and issues during everyday use. For instance, copying files to a Macbook proved impossible as we couldn’t switch the Zenfone 4 from USB charging. We also struggled to sign into some WiFi networks as the authentication option never appeared. Hopefully these are the kinds of issues that will be sorted in software updates.

What works?

Lots of unique, well-considered bonus modes and impressive customisation helps the Zenfone 4 to stand out from a lot of its rivals.

What doesn’t?

The sheer number of extra features could prove confusing for anyone not already comfortable with smartphones, although many of the bonus modes are at least explained the first time you use them. You’ll just need to hunt them down in the Zenfone’s settings first. We also saw a few little software bugs, which proved rather annoying.

Asus Zenfone 4 Review: Performance and battery life

While the Honor 9 packs Huawei’s highly capable Kirin 960 processor and the OnePlus 5 sports the beefy Snapdragon 835 chipset, Asus has gone for the more modest Snapdragon 630 platform. This means the Zenfone 4 isn’t as powerful as its competition in this price bracket.

We saw plenty of little stammers here and there in our week of testing; usually a pause of a second or two when opening apps. Our review handset also crashed a couple of times, often while using the camera, which to be fair may be down to the software rather than the hardware.

On the whole however the Snapdragon chipset can handle everyday use, with games and other quite demanding apps running smoothly enough. Plus, resource management plays a large part in keeping the Zenfone running smoothly.

For instance, Asus’ OptiFlex feature allows you to prioritise your favourite apps, allocating more processing power and memory to ensure a swift experience. You also have the Mobile Manager app which can clear the phone’s memory cache and wipe junk files from storage. This app can even track your data usage and warn you when you’re approaching your monthly limit.

Battery life is certainly more impressive, thanks to the energy efficiency of the Snapdragon 660 platform and Android Nougat. After a bedding-in period, we found we could get well over a day of life per charge, often stretching towards 48 full hours. That’s with a reasonable amount of camera use, web browsing, media streaming and the rest.

Thankfully the Zenfone charges quickly too, using the bundled Type-C charger.

What works?

The Snapdragon 630 is at least energy efficient, so you’ll happily get a full day of use per charge, and often close to two. As long as you don’t abuse the phone with non-stop media playback, of course.

What doesn’t?

Sadly the Zenfone 4 can’t come close to matching the performance of many rivals, including the OnePlus 5 and Honor 9, which cost the same or less. That means it will be less future-proof as well as generally slower.

Asus Zenfone 4 Review: Cameras

One of the stand-out features of the Zenfone 4, and the one which Asus is making the most noise about, is that dual-lens rear camera. Understandably so, too. You get a very similar setup to the excellent LG G6 optics, with a 12-megapixel f/1.8 aperture lens and Sony sensor backed by a secondary 8-megapixel wide-angle snapper, offering a 120-degree view of your surroundings.

Are dual-lens cameras really better than single-lens snappers? We’re glad you asked. Head on over to our dual lens explainer guide to see more on this double vision tech, including a run-down of the biggest and best smartphone snappers around.

We’ve fully tested the Zenfone 4’s camera tech so check out our in-depth Zenfone 4 camera review for all you need to know, as well as plenty of samples. For some of our favourite snappers right now, head over to our round-up of the best camera phones.

Asus Zenfone 4 unboxing, setup and hands-on review

Check out our full 20-minute hands-on review of the Zenfone 4 right now, over on our YouTube channel and below. This gives a close-up look at the hardware as well as an in-depth exploration of ZenUI, plus a full tour of the dual-lens camera and its features.

Asus Zenfone 4 Review: Verdict

The Zenfone 4 is one of the best smartphones that Asus has launched to date and it’s great to see the company’s handsets hitting the UK with gusto. However, can the manufacturer best known for its laptops and computing gear really do enough to sway consumers from the likes of the OnePlus 5?

Certainly there are plenty of great software features packed inside Asus’ ZenUI, which will particularly please parents and anyone who demands complete customisation. Meanwhile that dual-lens camera is good enough to create attractive long-lasting memories and boasts a solid wide-angle feature, making the phone a worthy consideration for Instagram obsessives. Media fans are also well catered for, in pretty much every department.

Still, the lack of serious power is a let-down, as the competition offers a lot more grunt for the same (or lesser) cost. Plus, the ZenUI overlay is a little buggy and quite poorly organised, which means many users likely won’t find some of the useful features buried within. It’s here where rivals steal the Zenfone’s thunder and make it a less essential purchase.

The Zenfone 4 launches in the UK in November 2017 and can be had SIM-free for £450.


Screen size5.5-inches
Screen resolution1920x1080
OSAndroid Nougat + ZenUI 4
Rear Camera12MP + 8MP wide angle
Front camera8MP
ProcessorSnapdragon 630
Storage64GB + microSD
Bonus featuresFingerprint sensor


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