Ars Technica posted a review on the KDE 4.0 desktop
A quote from the article:
>> KDE 4.0 Review
KDE 4.0 was officially released last week after extensive development. The long-awaited 4.0 release ushers in a new era for the popular open-source desktop environment and adds many intriguing new features and technologies. Unfortunately, the release comes with almost as many new bugs as it does features, and there is much work to be done before it sparkles like the 3.5.x series.
>> KDE 4.0 Review