We'll be looking into iOS 7 performance and battery life in greater detail in separate feature and/ore future update, mainly because most of our testing came during the beta phase of iOS 7 and some proper side-by-side testing is required.
That discounts any useful battery life observations at this stage, but we can confirm the iOS 7 runs absolutely fine on the iPhone 4S and upwards. The 4S is ever so slightly slower to load apps on iOS 7 than on iOS 6, but you need the two side-by-side to notice the difference.
We're in the middle of testing the iPhone 4 at the moment, which may prove more problematic given Apple has seen fit to disable some features for performance reasons. If you've got an iPhone 4, it's definitely worth waiting before you upgrade.
It’s a challenge to score an update to an operating system that comes free with Apple phones and tablets. In fact, how you view iOS 7 depends largely from what position you view it from.If you're an iPhone owner thinking of switching to Android, should you? Only if you really want a bigger screen. iOS 7 is a huge improvement on previous versions, one that's worth trying before you finally decide and one that extinguishes many most of the small irritations Apple has left untouched over the years. iOS 7 does enough to restore the faith in the software, though whether the iPhone 5S and iPhone 5C do enough is another matter.
Likewise, if you're an Android user considering switching to an iPhone, iOS 7 removes most of the reasons not to. You'll miss some of the deep Google integration, particularly Google Now, but you'll gain a thoroughly modern and super-slick OS and what remains the iPhone's biggest trump card, the App Store. It's not an open and shut case as there's more to the debate than just the software, but iOS 7 strengthens Apple's case considerably.
If you're a happy Apple user, iOS 7 is a revelation. Android fans will quip, with good reason, that you've been living in the dark ages for a while, but you finally have some ammunition to fire back that isn't just 'the App Store'. It's hardly a killer blow, but the debate over which is better can return to more philosophical questions and preferences rather than bemoaning the paucity of common features.
Of course, none of this will convince ardent Android users to make the switch, and nor should it. Yes, iOS 7 is a huge step forward for iOS, and it still trumps Android for simplicity and elegance, but it has nothing that Google or Microsoft urgently needs to copy, imitate or fear. It's a wonderfully competent, pure and seamless experience, but it's not a revolution.
Is that a bad thing? That depends entirely on how realistic your expectations are.
Next, read our iPhone 5S vs iPhone 5C comparison.