I'm that guy that has a new cell phone every couple months-- constantly trying to find one that I love from top to bottom, and I'm hard to please. I just swapped from a Treo600 to a Blackberry 7100t after an enticing set of deals.
My first impressions-- I'm so used to a touch screen from the Treo that I find myself tapping the screen wondering why nothing is happening! Setup was easy, synching was easy, so far so good. I bought PocketMac to synch with OS X, a small price to pay for the ease of proper compatibility. I wanted a device that could handle emails, address book, and calendar without the bulk of a Treo. My heart is with the Treo but its biggest downside was how bulky it was. The 7100t boasts some great features-- a brilliant color display, Bluetooth, Blackberry's web based client for address book and email setup and predictive text input with a QWERTY keyboard. I was concerned about how well the predictive text would work, having never really liked it on previous phones, but they definitely did a good job this time around. It's not quite like a Treo keypad, but typing is easy after you get the hang of it. I'll settle down with this for a few more weeks before I undoubtedly get enticed by a new mobile phone I just have to check out.