This is the first iPhone without a 3.5in screen, and the first to adopt the 16:9 widescreen format preferred by Android rivals. The width of the screen is the same as ever, and has the same resolution as the 4S (640 pixels), but the height has been increased from 960 to 1136 pixels, yielding a 4in display with the 'Retina' credentials of its predecessor. It's not quite 720p HD, but it's not far off (roughly 80% the number of pixels, fact fans).

The screen somehow feels closer than ever. A new manufacturing process means the touch sensors are now one with the LCD, which means the whole assemblage is thinner. It's still incredibly crisp, and it's more colourful. Blues and purples particularly ping, compared to the 4S, and photos look that bit shinier as a result. Compared to the yellowish Samsung Galaxy S3, whites are whiter and colours generally more natural.

The biggest change, of course, is the extra space. When moving from an older iPhone, the taller screen seems a little peculiar at first, but it's a matter of minutes before you wouldn't go back. We reckon it's a sensible size: 4in in a 16:9 ratio is just about big enough for movies on the move, and the extra space accommodates an extra line of apps and a few extra entries in lists and calendar views, all the while staying small enough for comfortable one handed use.

Could Apple have usefully gone bigger? The Galaxy S3 suggests it could, particularly for films and games, but Apple has its smaller-handed users to consider, and the resolution would also have had to increase to retain that Retina moniker. Oddly, the extra space isn't utilised by the landscape keyboard, which just has a couple of grey buffers to either size. A missed opportunity, we reckon.

Also, it's only Apple's own apps that take advantage of the extra screen space right now. Existing apps are confined to the central area of the screen with black 'untouchable' strips at either end, but essential iOS downloads are bound to be updated to fill the whole iPhone 5 display sooner than you can say 'widescreen Angry Birds Space.'

Glance at the iPhone 5 and it could very easily be a 4S: the flat edges and rounded corners are iconic to the point of being a little bit dreary. The back is where the action happens, as the glass has been mostly replaced by a panel of wraparound aluminium, leaving only glossy top and bottom strips.

On one side there's a slightly smaller (and less substantial-feeling) lock/mute switch next to the recognisable volume controls, while on the other there's a slot for the new Nano-SIM - if you're planning to upgrade to the iPhone 5 you're also going to need a new SIM card.

Pick it up for the first time and the reduced weight and thickness is rather striking. The 112g weight and 7.6mm thickness mean it's neither the lightest nor slimmest phone in Gadgetland, but it's not far off, and it is noticeably more pocketable than the Samsung Galaxy S3.

All told, the handset doesn't feel that aluminiumy, certainly not in the way aMacBook Air does, but the quality of finish is exemplary, particularly around its diamond-cut edges. It looks and feels as though the iPhone 5 has been styled for stealth rather than showing off, but we suspect that will please as many people as it disappoints.

We're torn as to whether it's an improvement over the 4S, though. On the one hand, it's a fresh look, and that back panel is drop-dead beautiful. On the other, the 4S'extra weight lends it a more substantial feel, and we worry about how long the 5's anodised finish will stay pristine. Let's call it a draw.

Thunderbolt and Lightning, very very frightening? If you've just bought a pricey iPhone dock it might be, because the iPhone 5 has ditched the almost-10-year-old 30-pin connector and replaced is with the tiny, all-digital Lightning connector, which means your new phone isn't going to fit.

Apple is launching two adapters, but they're expensive (although there are good DAC-flavoured reasons for the prices) and big enough to at best ruin the look of your sexy sound setup, and at worse ensure it doesn't fit at all.

But change is occasionally necessary, and Lightning is certainly more elegant than the 30-pin. It's reversible, it feels robust, and on the bright side it means we can expect a whole raft of new docks in the near future (Apple announced partnerships with audio luminaries Bose, Bowers & Wilkins and JBL on launch night). Lightning-to-HDMI and Lightning-to-VGA (yep, apparently one or two people out there still use VGA) adapters are also planned.

Straddling that Lightning port is a pair of tiny chassis screws, and beyond that are two sets of machined grilles, covering a microphone and a speaker. The latter won't get anyone body-popping, but it is loud and clear enough for hands-free calls, sat-nav instructions and irritating everybody on the bus. The 3.5mm headphone socket is, for the first time in iPhone history, on the bottom edge rather than the top.

But what should you plug into that headphone socket? Apple would implore you to try out the all-new EarPods, which come as standard. They look great, and they're a huge improvement over the old bundled buds, but they're not perfect. Apple has opted for one-size-fits-all comfort, so the EarPods sit outside the ear canal rather than burrow right in. That means there's very little noise isolation, so you'll be able to hear what everyone around you is chuntering on about and they'll be able to hear you listening to Luther Vandross.

If you're the make-do type when it comes to headphones you'll be getting far better sound quality from your bundled buds this time around, but if you have even a passing interest in sound quality you should budget for a better pair, such as the SoundMagic E10s.

The new processor, Apple's A6, makes a palpable difference to the overall speed of the iPhone 5. Compared to the iPhone 4S there are shorter in-app loading times, smoother 2D and 3D graphics and a general reduction in waiting when you're zipping around from one app to another. Siri opens immediately, adding attachments to email is completely lag-free, the camera is up and running almost instantly, and that chip means it's now also capable of snapping a full-res shot during 1080p capture. If that doesn't sound quite exciting enough, allow us to be more definitive – this is the fastest, smoothest, most seamless smartphone experience money can buy.

A little bit of casual benchmarking using the GLBenchmark Egypt High test yielded a score of 6766, while the iPhone 4S got 1158. The Offscreen test was closer: 16681 vs 8346. This looks like a lot more than day to day usage bears out, but it suggests that there's headroom for the iPhone 5 to do some pretty impressive stuff.

On paper the iPhone 5's snapper looks very similar to the iPhone 4S' – same 8MP resolution, same f/2.4 lens. But there have been upgrades. 1080p video is excellent for a phone, matching the Samsung Galaxy S3's footage in good conditions and beating it whenever the lighting conditions throw up challenges such as high contrast or general gloominess.

The iPhone 5 is equally capable when capturing stills, with a neat new Panorama feature and the ability to dig up detail from twilight and indoor scenarios that's remarkable by smartphone standards. Just look at these sample images for a comparison: iPhone 4S above, iPhone 5 below.

On the downside, the lens is still in the wrong place. It looks neat tucked into that corner, but it makes the phone hard to handle in landscape mode – and it's all too easy to blot out vital footage with a drifting digit.

Even more familiar than the iPhone 5's design is the grid of apps that makes up its iOS homescreen. The way iOS works hasn't really changed since 2007, and iOS 6sticks pretty rigidly to the programme. While certain Stuffers are among those looking for a more fundamental update that would give the iPhone a 'living' feeling as seen in Android's widgets and Windows Phone's live tiles, beneath iOS 6's familiar looks are a number of handy tweaks.

There are obvious touches, such as the 'New' flash that appears across across the icons of any app you've just downloaded, and the sticky gum visual that stretches from the top of the email app as you drag down the list to pull in new messages. Then there's the new 'Do Not Disturb' feature hidden in the settings menu, which allows you to specify how contactable you are to different callers.

Social features have had subtle upgrades, too. Facebook is now just as integrated as Twitter, allowing you to post photos direct from the (also subtly upgraded) Photos app and using Siri. Friends' birthdays appear in Calendar and phone numbers in Contacts. Got too many friends? Birthdays every day? You should have thought of that before you befriended them all.

The shared Photo Stream can be set to send a notification to your nearest and dearest whenever you add a new photo, Facetime now works over 3G as well as Wi-Fi, and there's a VIP inbox into which messages from your chosen contacts are automatically filtered and that notifies you whenever you receive an important missive. Just as usefully, you can now assign different email signatures to different accounts.

Nothing is exactly revolutionary, though. Apple has decided that iOS isn't broken and so hasn't issued a fix. To be fair, it's a brilliantly intuitive operating system to live with; it's just that the widget-based homescreens of Android are more exciting, more instantly informative and more, well, new. For now this link in the iPhone's chain is holding, but it's weakening.

Both the onboard iTunes and the App Store apps have been given a refresh and now look much more like their desktop counterparts, pulling in more information on each page and reading less like a list. There are now numerous flickable carousels to browse and tabs to click on for more comprehensive user reviews and ratings. As with many of the iOS tweaks, these changes are so intuitive that you might not even notice at first, but in the long-run this is a slicker, more user-friendly and better looking digital shopping experience.

As for apps in general, they mostly run with those aforementioned untouchable black bars – but that doesn't stop the variety and quality on offer being head and shoulders above those on Android and Windows Phone. The huge pile of entertainment and productivity that is the App Store remains iOS' killer feature.

Much has been made of the severance of Google Maps from iOS 6, and rightly so – navigation is now a fundamental feature of the smartphone experience. Google Maps got the heave-ho so that Apple could introduce its own map app, and for users the switch is something of a mixed blessing.

The headline feature is 'Flyover', which introduces interactive 3D city models. Coverage is currently limited to a handful of cities worldwide, and the practical applications of the tech are limited, but we challenge your jaw not to drop as you zoom in and spin your map around the circumference of London's Gherkin. A gimmick? Sure, but one that we've fallen for wholeheartedly.

On the other hand, Maps can also be used as a full-on sat-nav, with voice-augmented turn-by-turn navigation, ETA, live traffic updates and more. It's decent, but a distance behind Android's Google Maps in terms of its search skills and knowledge of the vagaries of local dead ends and one-way systems. 

LATEST UPDATE: Don't call it a comeback but the arrival of a Google Maps appmeans the iPhone 5 has jumped above the HTC One X+ in Top Ten Smartphones.

iOS 6 has brought with it some neat new features to make Siri far more useful. For example, we asked the poorly constructed question "What are the best films showing around here later on today?", and Siri almost immediately presented us with a list of films showing that evening in our two nearest cinemas, ranked according to their score on Rotten Tomatoes. Dredd was ranked higher than The Dark Knight Rises, but we're not going to hold Siri accountable for that.

We followed up with "How did Tottenham do at the weekend?" and were treated to the glorious 3-1 scoreline Spurs recorded over Reading two days previously, closely followed by a deflating look at the Premier League table. Services are limited (the football results are Premier League-only), but we do also get the local businesses functionality that our US cousins have been enjoying since launch. Most importantly, there's been a significant improvement in Siri's ability to turn convoluted questions and commands into worthwhile responses, making the whole experience more natural and conversational.

There's also a boost for home users thanks to dual-band wireless-n Wi-Fi. Again, this makes for extremely nippy downloading – in our experience, the iPhone 5 installed new apps in about half the time that the iPhone 4S took.

Call quality is supposedly also top-of-the-line on the iPhone 5, although we have to say, we didn't notice. It supports HD Voice services, using a better audio codec to make speech clearer. Again, we didn't get to test this, but as it was, phone calling seemed just fine. There was no noticeable 'death grip', and the dialler has also been neatly redesigned for the bigger screen.

If you, as we, were hoping Apple was going to give NFC the shot in the arm it so desperately needs, we have bad news – waving your iPhone at the contactless pay machine in Marks & Spencer will get you nothing but odd looks from staff. However, Apple has added an app to iOS 6 called Passbook, which allows you to keep all of your loyalty cards, gig tickets and boarding passes in a single, digital wallet. Think of the British Airways app, which makes checking in and progressing through the airport a simple, paper-free affair, and you're on the right lines.

Passbook is also location- and time-aware, so will fling up your boarding passes when you're at the airport or show you your cinema tickets just before the show. In theory, anyway – it wasn't live at time of testing.

In our tests the iPhone 5 lasted just as long as its predecessor, and you can expect to get 8-10 hours of normal use out of it and up to five hours of heavy use, watching YouTube over Wi-Fi for instance. Most will need to charge it every evening, but eco-users could eke out an extra day. It won't generally be gasping for a charge at bedtime unless you've been indulging in serious gaming, tweeting or sat-navving during the day.

The iPhone 5 is not cheap. If you're going SIM-free, prices start at RS. 37000 for the 16GB version and rise to an eye-watering RS. 42000 for 64GB.

Many will be going down the contract route, which is why we've put together a comprehensive guide to the best iPhone tariffs on all the major networks. To cut a long story short, an iPhone 5 contract will still cost you more than one for any other phone, and that's before you factor in EE's 4G tariffs, which haven't yet been announced.

So is the iPhone 5 worth the money? And has Apple done enough to reclaim the top smartphone spot?

In the flesh the iPhone 5 is a delight. And if it feels just right, it performs even better with flawless operation, an excellent camera and a screen that's downright stunning. It's not flashy and it's not radical but it is a significant improvement over what was already an excellent device and it still has the best selection of apps available on any handset. 

But we can't ignore the chink that iOS 6 creates in the iPhone 5's armour. With Google Maps in exile and Apple's own Maps app performing considerably below par, the iPhone 5 – not to mention any previous iPhones or iPads updated to iOS 6 – is trailing behind in one crucial way. Put simply, you just can't trust the maps on an iPhone any more.

It's still a 5-star handset, and it has the potential to be the best phone you can buy. So, Apple – hurry up and fix the maps, won't you?