The interface of the iPhone 6, despite launching with iOS 8 and subsequently shifting to iOS 9, iOS 10 and iOS 11, is still very familiar for anyone who's used a smaller iPhone or an iPad over the last several years. 

With the iPhone 6 you've actually got another option to make the view bigger (or zoomed in) in order to service those that perhaps don't have the best vision, and don't want to squint at the larger screen.

iOS 8 also added some very clever UI tweaks here and there, such as the ability to save contacts (with info like phone numbers from the signature) directly from the email app.

Then there's the 'Reachability' option. Double tapping on the home key without pressing it in will make the screen drop down around two-fifths, enabling you to easily press anything at the top of the screen. It's a slightly messy way of doing things, and despite trying my utmost I could rarely remember to activate it.

Still, at least Apple is showing that it's still a bit disgruntled at being forced to bring a larger phone to the masses, and is trying to mitigate the problem.

One of the most impressive features introduced by iOS 8 was the ability to swipe back and forth through the OS to get through apps and pages on the web. It's not a new feature for the average smartphone user at all – it's got some elements of BB10 (in terms of swiping to get to new menus), and there are more than a few nods to Android in there as well.

But that's not a bad thing in my mind. As long as a method isn't patented, then the more you can do to add a feature in to make a user's experience smoother, the better.

It's not a completely useful system, as the swipe doesn't work as a complete back key. To be perfect, I'd have liked to see a swipe backwards on the first screen of an app or web page as a method of getting back to the home screen.

It's things like that which embed the action into muscle memory, rather than being able to do something when you remember it's possible. However, it did severely limit the need to press the back button in the bottom left-hand corner (admittedly an improvement over iOS 8's top left corner), which is a plus.

While iOS 8 introduced all of these new features and more, it's no longer the most current version of Apple's mobile OS. In news that will neither shock nor surprise you, the iPhone 6 now ships with (or can be upgraded to) iOS 10.3.

This adds the all-new News app, imbues Siri with scary levels of intuition and even upgrades Apple Maps with public transport directions. It's also now easier to tell whether or not you're typing in caps, and app download sizes have also been given a trim through a feature called 'App Thinning', saving valuable storage space (especially useful if you opt for the wholly inadequate 16GB model).

In fact, iOS 9 itself has received a few updates of its own, many of which benefit the iPhone 6 as much as any of Apple's newer devices. For example, iOS 9.1 added more than 150 emojis to the keyboard, which has the potential to make your messaging that bit more expressive/obnoxious. Let's hear it for the taco. Anyone?

The big addition in iOS 9.2, meanwhile, has been Mail Drop. This previously Mac-only feature enables you to send large files through email, making it possible to share them without having to send them to Dropbox (or some other cloud storage solution) first. It's very well integrated too, so iOS will simply offer you the option of using it any time you try to send a particularly large file.

iOS 9.3 brought with it relatively minor updates to various stock Apple apps and a new feature in Night Shift. This new function is tasked with increasing color temperature as you near bedtime, making the the display warmer and helping you sleep better - or so Apple claims.

Most recently however, in 2017, the iPhone 6 was upgraded to iOS 11, keeping the handset relevant three years after its initial launch. 

It's good to see Apple supporting legacy devices like the iPhone 6, but it's fair to say it struggles a little with the latest software and you may witness slower performance and reduced battery life.

iPhone 6 review

Quick contact access and Siri

Another change relates to the quick access to key contacts. In iOS 8, a 'recent contacts' bubble gallery was added at the top of the multitasking menu, which as is still accessed through a double press of the home button.

From iOS 9, however, this was added to the new Spotlight Search screen, which is accessed by swiping right from the first home screen. In practice, this grants more space to the multitasking menu, making it easier to dip in and check out details from another app. It also makes sense to lump all of Siri's constantly shifting suggestions in one section.

However, I dislike features that try and choose these things for you. I'd rather be able to hard-code contacts there, as unpredictability in new features can be infuriating.

As such I didn't really use this feature that often – but if you remember to swipe right to get to the most used people, then hopefully over time it will populate correctly for you and you'll end up using it instinctively.

Going back to Siri, Apple's personal assistant is now proactive, being able to make suggestions of its own, such as appointments you might want to add to your calendar.

Interactive notifications

The other big thing that Apple introduced with iOS 8 and improved in iOS 9 is the interactive notifications and widgets for the main drag-down menu that pervades throughout the app.

The interactive part is, again, nothing new, as it's something that's been part of other phones (for example, the LG G3 and G4) for a number of years. However, it's a very slick and unobtrusive system here, with a small banner appearing at the top of the screen.

Replying to a message instantly is cool, and something that really does bring an element of joy and usability to the system. Other apps can use this method of alert too, but not to the same effect. For instance, Mail coming in will show up in the same banner, but you can only organise the message rather than reply there and then.

I appreciate that emails are generally longer, but there should be the option to fire off a quick missive if the situation calls for it.

The widgets in the Notifications drop-down are pretty cool, particularly now that third-party app developers are incorporating them as standard.

There are now more options available in the notifications bar to make a quick tap all you need to do things on the fly. It's one of those things that when you notice it for the first time, it's really useful, but quickly becomes commoditised.

iPhone 6 review

The rest of the interface is much as expected for an iPhone - and that's a good thing in the eyes of most users. However, I will say that the touchscreen on the iPhone 6 isn't as good as the competition – it doesn't feel as responsive as the Project Butter / Project Svelte (and subsequent evolutions) that Android has been adding into the backend of its platform.

The problem manifests itself when swiping laterally through apps, and the internet browser doesn't always have that super smooth reaction that I've come to expect from a modern smartphone.

I'm being really picky here, as it's not a nuisance, but at the same time it's perceptible compared to the competition, although nothing out of the ordinary for your average Apple user.

Maybe it's down to the lower 1GB of RAM Apple has packed in – the 2GB iPhone 6S is one of the most fluid phones around, after all. But although it's slight, those hopping between Android and iOS might pick up on the lag.

The better news is the crashes that plagued the early iOS 7 devices seem to be pretty much cleared up with the iPhone 6 on iOS 9 – I only noticed Spotify giving up the ghost during my setup, as well as one Facebook crash where before Safari was falling apart all over the place.

Dropbox did hate downloading large files when you moved the phone, but that feels like more of a bug with iOS 8 compatibility than an endemic failure. It all seems to be running well in iOS 9.2.1.

These things are often software-related, of course, but ultimately the iPhone 6 seems more stable out of the box than its predecessor.

The rest of the iPhone 6 interface is simplicity itself. I'm never going to be happy with the way many apps still have their personal settings only available in the general Settings app, but at least more are starting to let you edit functionality from within the app itself.

The iPhone 6 interface is clear, clean and as you'd expect. I still think there's more to be done with the Notifications area, but at least it's less complicated than before. Splitting it into two still feels wrong, and the calendar / traffic / summary info seems more power user than standard Apple buyer.

The Control Center at the bottom of any screen is richer than before too, and still gives access to the key areas, including music control from anywhere within the phone.

iPhone 6 review

Is it the perfect interface for customisation? No, and many people are starting to want more from their smartphone, which is why Android phones are proving so popular.

But it's still got the core simplicity that Apple has prided itself upon for years, and that's still going to be a massive draw, especially for those that feel like 'they know where they are' with iPhones.

Performance

Providing the power behind the scenes on the iPhone 6 is a 1.39GHz dual-core A8 processor with 64-bit architecture and 1GB of RAM.

The iPhone 6 seems to be a little bit slicker than the iPhone 6 Plus when it comes to chugging away under the finger, although when looking at the Geekbench 3 scores we can see it's almost identical (average score of 2905 vs 2911 for the 6 Plus).

This puts it below 2015's crop of flagship smartphones such as the Samsung Galaxy S6 and HTC One M9, but right with the Samsung Galaxy S5 and below the One M8 – although HTC admitted to slightly gaming the results with a special 'high power mode'.

In short, despite the dual-core processor, Apple seems to have eked out enough power to make the iPhone 6 a strong enough contender day to day, but if you want more power there's always the newer iPhone 6S now. Its processor is a good 40% faster than the iPhone 6's, and you can feel the extra snappiness in general usage.