My girlfriend's iPhone 4s updated to iOS7 and refused to activate. After four or five hours of going through support and then a trip to the Apple store, Apple confirmed that the hardware was fine but something went wrong on the upgrade. The "Genuis" told us that's it's "unfortunate" that things like wifi sometimes break when you upgrade your phone's OS because of the stress that it puts your phone through. Their only solution was to buy a used phone of the same model for $200 from them. Our request to have downgrade back to iOS6 (we have both an iTunes backup and an iCloud backup) was refused because the "Genuises" can't even do it. I even offered to pay them to fix that phone and we were told they couldn't do it.

We refused to pay Apple to replace her phone and I bought her a friend's spare phone in the meanwhile. My first and only bad experience with Apple so far but quite disappointing to say the least.