I spent 2 hours this week trying to upgrade, back-up, restore, etc a relative's phone, without success. The fact that you can't downgrade from iOS 7 makes this doubly painful. Support from Apple was pretty straightforward for my friend: "Your phone is out of warranty, sorry, we will not help you." The fact that this warranty is illegal under EU law is left out.
Finding that this is an incredibly common problem amongst users with a recent iPhone (4S, still being sold by Apple), and seeing that Apple is actively censoring people for offering warranty help, is very frustrating. It's sad that it takes someone famous ranting about Apple's censorship to solve the issue, when it all could have been avoided by saying "We are aware of the problem, it has to do with the iOS 7 upgrade, we are working on a software fix, if we can't fix it we will replace the affected iPhones."