Pros:
Small, light and lean. Feels comfortable in hand and doesn't feel like you are holding a brick.
Long Battery life. Will last a whole day with bluetooth, 4 multiple email programs, 2 IM programs, Twitter, Facebook running concurrently
The Blackberry OS 4.5 runs smooth without any hangups, sluggishness. It supports MMS, Multitasking, Cut-Copy-Paste, and a whole slew of smart features. For example, you can dial 1-800-BEST-BUY just off the keyboard just as common sense would dictate since you have a QWERTY keyboard and it just works.
Ample Keyboard shortcuts and they are intuitive. For example, when you open Calenader, to go the month view, press 'm'. To go to the next day, press 'n'. Same goes for viewing messages in your Inbox. Press 'p' to view the previous message. Select multiple messages and press backspace key to delete them. Having shortcuts directly translates into shorter menu navigation and thus saves time.
OTA (Over the Air) installation of apps removes the PC from the picture as it should be. And the Blackberry App World offers easy accessibility to a wide variety of programs. Purchasing and installing apps has never been so smooth just like the Apple Itunes Apps.


Cons:
Screens get smudged with fingerprints easily.
Batter life can never be enough.
Some models lack Wifi.
Lack of hardware button to silence phone like on the Palm Treos.
Lack of inbuilt programs to unzip files.