Asus 6z (6GB RAM, 128GB)  +2 variations

Design

• Beautiful, stand-out design - a curved rear that fits nicely into the palm of your hand, a glossy back, and most importantly, a 6.4 in full-screen display free of bezels and notches
• A neatly positioned, well thought-out alert and charge light - in the top right corner just above the screen
• A handy, configurable Smart Key (defaults to Google Assistant) - you can configure it to have specific single-press, double-press and long-press actions
• The physical fingerprint sensor at the back is fast, and conveniently positioned, for both left- and right-handed use
• Like all glossy backs do, this one too will attract a lot of fingerprints
• Relatively hefty (190g)
• Face unlock is not as quick as on other competing phones with the time taken to flip the rear camera forward adding a little delay

Display

• Large, clear, immersive 6.4-inch screen with minimal bezels, and of course, no notch
• But the screen is LCD, rather than OLED, so it's not quite as gorgeous as the AMOLED on the OnePlus 7

Software

• ZenUI 6 is leaner, faster, more streamlined than before, and close-to-stock Android - making it now one of the best and most clean Android UI implementations around, along with OxygenOS
• There are range of tweaks of course - OptiFlex (learns which apps you use and loads them faster than the norm), Dark Mode (essentially replaces the white background with a black one easing eye strain), Smart Volume (sets media, ringtones and call volume to a level appropriate to ambient noise) - there are plenty of other tweaks too, but they are less obtrusive than previous iterations of ZenUI
• Asus also adds a range of its own apps including a gallery, file manager, weather app, data transfer tool, sound recorder and its own camera app - which are handy - and there is no unnecessary bloat

Performance

• Top-end flagship performance with the flagship Snapdragon 855 underneath - the Zenfone 6 is in fact one of the cheapest phones at present to pack the 855

Camera

• Of course, the highlight of the Zenfone 6 is the clever, unique flip camera system
• Asus has thought not just about removing the front camera for the 'full screen' experience, but also about enhancing the camera's usability - the result is not just another pop-up design - open the camera app and the dual rear-facing lenses are used in the usual way - switch to selfie mode and the camera housing swings out from the back of the handset until the two lenses sit proud of the top of the phone, facing forwards!
• The camera system consists of dual cameras - a 48MP primary camera + a 13MP ultra-wide camera, that can create some cool framing opportunities
• The image quality is very impressive - even considering the excellent competition - in daylight shots, you can expect a great deal of detail, while indoor shots too capture texture and detail well
• The special camera setup means there are a bunch of smart features, like motion tracking (set this off and the camera will follow a moving subject, as long as it's moving slowly), and a motorized panorama mode (select it and hold the camera steady, and the flip lens moves through its full 180 degrees, shooting as it goes)
• Night mode shooting captures quite a lot of detail
• Great video quality, with very capable stabilization, and range of video modes - the ability to record at 4K@60fps with EIS is a nice touch, too
• Finally, of course, the best outcome from the flip camera mechanism is that you now get to use the same excellent rear cameras as your front cameras as well - this means that the selfie quality is pretty much unrivalled, when compared to even the best of camera phones
• There is some added shot-framing flexibility as well - if you hold the selfie button a slider pops up that can be used to rotate the camera housing into a particular position -- perhaps using it as a stand, or to get a shot that's at an awkward angle
• Finally, what you are getting is excellent quality in daylight and low light, image and video, front and back - making for one of the best camera phones, especially in this price bracket (and yes, it's a significant way ahead of the OnePlus 7)
• The only phone in this price bracket that is arguably a bit better in overall camera quality is the Pixel 3a

Audio

• Nice stereo speakers - they deliver plenty of volume, and reasonably good quality

Battery

• The other big highlight of the Zenfone 6, apart from the flip camera setup, is the exceptional, class-leading battery life, powered by a huge 5000mAH battery - you are going to get 2 days of use from this beast with moderate use
• Quick Charge 4.0 support

Verdict

• No 2 ways about it, Asus has delivered a surprising capable, sublime mid-ranger here, and given OnePlus a lot to worry about
• A great camera setup, and an excellent battery life are the highlights - and add to that some nice-to-haves that are increasingly harder to find in the high-end segment like a headphone jack, a status LED, and a dedicated microSD slot, and you can see how the Zenfone 6 makes a really compelling case for itself
• The 2 main competitors will be the OnePlus 7 (better AMOLED display, but not as good cameras), and Pixel 3a (better cameras, but behind in most other areas) - and the Zenfone 6 is likely to compete well against these champions