I've been living with Apple's new operating system for the iPhone, iOS4 , for a week now. I rarely jump so quickly to a new major version of software on a device I use every day, but I seem to have a little more time on my hands than usual at the moment, so decided to take the plunge on launch day. Was this a good idea? Possibly. I decided to risk the upgrade on Monday 21st June because the new features it offered were extremely attractive. In particular being able to store apps in folders, and the support for multiple Exchange profiles for e-mail and calendar, along with a unified inbox. The multi-tasking was less attractive to me, offering something more akin to a task switcher than true multi-tasking. So, how has it been?