It is so good to see that a lot of work during KDE4 development went into improving the quality of the user experience. Unlike their KDE3 counterparts, the best KDE4 applications are definitely more user-oriented. Despite being a developer, I enjoy this as much as every other person would. It is equally good to see almost all KDE4 applications being fast. The optimizations behind the scene in Qt and KDE frameworks already showed up, but I think that this is only a start. We will definitely see even more performance improvements in the future.