Hi, My wife's iphone 4 is on ios 6.0.1 and I want to update her phone to ios 7.1.1. Has anyone done this and how is the performance? It's pretty zippy with 6.0.1 and I've heard horror stories about ios 7 on iphone 4s e.g. lag, unresponsive touchscreen etc. Has 7.1.1 made a difference or should I leave well enough alone? She mainly uses the iPhone for regular stuff like facebook, web, email. Thanks.