My iPhone has developed an intermittent fault after only 10 days - every now and again when receiving a call/sms, the screen just goes blank white, and the only way to get a response is to switch the phone off and back on. A factory restore didn't resolve the matter. After two calls to Apple they said they'd take it back to test, and possibly send a replacement. All of which would take two weeks! For a 10-day old unit! I took it back to the O2 store, but they'd only replace it if I could demonstrate the fault. As it's intermittent this wasn't really feasible. Since I only signed my contract with O2 13 days ago I'm cancelling it and starting another one. A bit of an extreme measure, but the only way around it. Apparently, signing up to a business tariff gets you next day handset replacement. Something to bear in mind.