The first thing you notice about the 5S is its new Home button. It doubles as a fingerprint scanner, so you can unlock the phone and sign into your Apple account simply by touching it. The reader has already caused a huge amount of controversy, but there’s no denying that this is a convenient – and seriously cool – feature.

iPhone 5S review: Performance

Apple’s new 64-bit processor is partly to thank for the the fingerprint reader. It’s remarkably fast and means there’s no delay in reading your finger and unlocking the phone.

The A7 chip also makes iOS 7 run smoothly. There’s no juddering or stuttering when swiping between home screens, or when the wallpaper moves around in the background. Apps launch and web pages load faster than ever. See also: iOS 7 review

The A7 also has a motion co-processor – the M7 – which will come into its own when the developers of activity tracking apps update their software to use the new chip. It should mean the 5S can replace the likes of a Fitbit or Withings Pulse.

iPhone 5S gold, white, space grey

iPhone 5S review: Cameras

Both of the iPhone 5S’ cameras have been upgraded, although the number of megapixels stays the same. Instead, the pixels are bigger which means better quality in low light. Plus, the rear flash now has two LEDs, one of which is amber. It makes for much more natural-looking photos in the dark.

There’s also a new burst mode which takes 10 photos per second until you take your finger off the shutter button.

iPhone 5S gold

iPhone 5S review: Display and wireless

One thing that hasn’t changed is the 4in Retina display. It’s identical to the iPhone 5’s and is still a decent screen. However, compared to the larger, Full HD displays of the iPhone 5S’s rivals, the screen is starting to feel a bit cramped.

The phone itself is the same size and weight as before, so most cases designed for the iPhone 5 will fit, but those with a small hole for the camera might block the new flash.

It’s slightly disappointing that Apple hasn’t updated Wi-Fi to the new 802.11ac standard, but support for more LTE bands means that, in the future when contracts are in place, you’ll be able to roa on 4G in more places than you can with an iPhone 5.

iPhone 5S review: Verdict

If you already own an iPhone 5, it’s hard to justify upgrading to the 5S. Yes, it’s considerably faster and takes better photos and videos in low light, but the 5 is still a great smartphone and has at least another year in it before apps (and possibly iOS 8) start to find the A6 processor’s limits.

Those with a 4S (or iPhone 4) are in for a treat, though. As well as serious performance gains, the bigger screen and lighter weight make a huge difference, and the fingerprint scanner is a bonus.

Ultimately, if you want an iPhone, the 5S won’t disappoint and is one of the most future-proof of the current smartphone crop.