Here's some links that may convince you:
Why BlackBerry?
And here's some useful info:
BlackBerry FAQ
Even though BlackBerries are sometimes more expensive than Hiptop/sidekick, don't forget that BlackBerries has more free software applications available than (BlackChat ICQ, BBLight, BBToday, Berry411, jmIRC, midpssh, etc). On top of the existing great pay applications that has free trail versions available (Verichat, Idokorro, etc.).
Just make sure you get one of the newer BlackBerry models with screens that are just as colorful as the Hiptop/Sidekick, and in many cases, better looking graphics:
BlackBerry 7250, 7520, 7290, 7100