"As Seigo noted on Twitter last week, there were over 2,000 commits to the KDE source code between when KDE 4.0 was tagged and the day it was actually released. That's a tremendous amount of code churn, and much of that is probably bug fixes."
"I encourage those of you who are testing KDE 4.0 to help out by submitting bug reports."
It's really buggy and lacks of some basic functionality. KDE developers are working hard, so I'm confident that 4.1 will be really nice release.