i'm using two devices at the same time .
BlackBerry Torch and iPhone 4.
now let's compare the two ( out of the box experience)
the iPhone is an Excellent multi media device and a very good Web browser.
the Blackberry on the other hand excels in Notification and E-mail handling. That may not be important for most consumers, but having more than 1 email account which requires different Signatures ( not the usual " sent from my iphone") and the ease of attachments.
the BB comes with FREE documents to go etc, unlike with the iPhone 4 where i have to purchase pages, numbers etc separately.
the other thing is having different tones for different applications, x for BBM, y for Facebook notification, z for SMS etc.
ADD some colors ( through the LED ) and you don't even have to take the phone from the holster anymore, just look at the blinking light and you know what and who's trying to reach you.
Lastly, the user replaceable battery, with my 3G before, i'm always tied to a charger whether it's the car or the office outlet.
but with a BB you can buy a spare battery and swap it.