I have a BlackBerry (recently upgraded to a Storm2) for several reasons, some out of necessity and others because it does some things better than my iPhone 3GS. I still have my iPhone 3GS, but it gets far, far less use lately.
- Tight, secure integration with my corporate email, calendaring and directory server. I have HIPAA-protected information on my phone which needs to remain secure. The iPhone OS 3.x currently just doesn't have sufficient encryption/security. This point simply can't be argued.
- Unified inbox for all my email accounts. Quite handy, actually. Can't be done (at least not yet) on the iPhone. Not a deal-breaker, but nice to have.
- It runs on a non-AT&T carrier. Far, far too many dropped calls on the iPhone. It's very unprofessional to have to call back 3 times in one conversation because your phone can't keep hold of a usable signal. Also, there is zero AT&T penetration into the buildings at work. The iPhone was virtually unusable as a phone at work. I get full 5-bar coverage inside with my Storm2.
- Attachments. I can actually open, edit, save and re-email attachments on my BlackBerry. Not so on the iPhone; the iPhone can view and forward, but good luck trying to edit anything.
- User accessible file system. Doesn't exist on the iPhone. Save, edit, rename, resend, etc...
- Multitasking. Personal things like Facebook and my little weather app, and professional things like Epocrates all continue to run in the background, updating themselves when necessary. Yes, Apple's push notification provides some of this functionality, but not all of it.
- I can carry a spare battery for my BlackBerry. While I'd say the battery life of the Storm2 and iPhone 3GS are nearly the same, there are times when I'm simply away from an outlet. It's easy to carry a fully-charged spare battery in a suit pocket. The battery is not much bigger than a matchbook.
Now, the iPhone wins hands down in terms of UI and app availability and has a much better media player, but my Storm2 has a reasonably functional music player and movie viewer, and it'll even play all the same formats the iPhone will (save the Apple DRM-protected stuff, of which I have very little). Plus, the removable microSD card does come in handy; I've got 16GB in it now and can upgrade it to a 32GB card if I so choose.
And for apps, while Apple obviously wins, I have BlackBerry equivalents for everything I need - Open Table, Pandora/Slacker, Facebook, Docs to Go, Poynt, TiVo scheduler, VCast Song ID (like Shazam), Google Maps/BlackBerry Maps, and there's even an Urban Spoon for BlackBerry.
And, yes, the web browser for the BlackBerry is inferior to the iPhone's or Android's. But the broswer for OS 5 isn't quite as bad as people make it seem. And if there's still a browsing issue, Opera Mobile 5 does a very good job as well.
OS 5 for the newer BlackBerry devices correct a lot of minor issues, such as adding threaded SMS like the iPhone has and features kinetic flick-type scrolling on my Storm2 like the iPhone's. Performance-wise, the Storm2 is easily as responsive as the iPhone 3G in terms of scrolling, apps opening/closing/running, etc.
I had a BlackBerry Tour, but grew tired of the mechanical trackball and found the screen and keyboard too small. The landscape keyboard on the Storm2 works really well for me, and I can type quite fast on it - faster than on the iPhone or on the BB Tour. I actually really like the click screen on the Storm2 (never used a Storm 1). And at 40 years old, I prefer the larger screen size of a widescreen touch display.
So, there's my BlackBerry story.