I have been using twitterberry for awhile and wasn't thrilled with it. I didn't like how you couldn't reply to people and the updates are not so frequent.
After looking at berryreview I see there is a new app called tinytwitter
Has a scrolling bar on the bottom with latest twits and is easy to use and works fast...
check it out at berryreview TinyTwitter - Twitter For Free From Your BlackBerry | BerryReview
I have already removed twitterberry.