Most people who still use a Blackberry live on e-mail. Here is a post by a reporter for ZDNet that explains his woes going from Blackberry to iPhone and back to Blackberry.

Saying goodbye to my iPhone, the data hog

After flirting with an iPhone for a month, here's why I switched back to a BlackBerry. The iPhone was fun, don't get me wrong, but I know where my loyalties lie.

Here is the author's usage that gives you an idea of his perspective.

I get between 200-250 emails on an average day. I receive roughly 20-30 tweets or direct messages a day. I get dozens of Facebook notifications, calendar alarms, and numerous phone calls. Each and every time, my BlackBerry vibrates for a whole second, and the LED notifier flashes. Yet even with this, my battery lasts two days without needing to charge, while an iPhone seemingly lasts for only 12-14 hours without charge, but only if small animals are not sacrificed to the Apple gods at regular intervals.

This isn't a story you often hear. The author closes with his conclusion he wants a Blackberry.

My business and work partner for a month, my iPhone. It was fun, don't get me wrong, but I know where my loyalties lie. And perhaps that's what makes the general consumer market so different. We want, we take, and we rarely focus on what we actually need. I need my BlackBerry, and while I still want an iPhone, I know full well it will take time before it needs me.

Unfortunately for RIM this is a minority.