But, most of TheStreet.com's readers use Research In Motion ( RIMM) Blackberry devices to get their mobile email. Not Windows ( MSFT) Mobile-based phones. Not Palm ( PALM) OS-based phones. Not Symbian ( NOK) or Linux-based either.

So, when the best consumer-oriented smartphone in the world adds enterprise email to its feature portfolio, TSC readers want to know if it's time to dump their "Crackberries" and buy an iPhone.

I'm sorry to say that the answer to that is -- not yet.

In our tests, iPhone batteries really can't handle the extra drain of Microsoft Exchange mail. Blame it mostly on Microsoft.

Microsoft's mobile email software is a pig. It always has been a battery hog. Everyone who has ever lived with a Microsoft Mobile phone knows that battery life stinks if you constantly "push" email to your device. That's why I'm surprised that Apple chose to default their Exchange mail software to "push" email. If you set up your phone without changing that setting, you will get only four to five hours before you have to recharge the battery.

If you change the 3G's settings to "pull" email ("fetch" in iPhonese), having your phone ask the server for new mail every 15, 30 or 60 minutes, you will extend your phone's battery life approximately five to eight hours before you get a low battery warning (less than 20% left).

If you compare these numbers to other Microsoft-based phones, like the new 3G Palm ( PALM) 800w for instance, you find that the iPhone falls way short. The 800w also gets lousy battery life (5.5 hours) on "push" mail -- but if you set it to "pull" email every five minutes (a setting not available on the iPhone 3G), battery life on the new Palm rockets to 36 hours. That's a big difference.

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