The KDE Plasma desktop is one of the best known within the Linux world, being the default desktop environment for both openSUSE and Fedora, to name just a couple of the best known distributions that use it.
A very stable desktop environment.
KDE is in continuous development. With the arrival of the fourth generation of KDE, the developers managed to achieve a great increase in the quality and aspect of the desktop and its adaptability to different themes and effects, and all this added to an increase in its response speed at the same time that it required less of the system's memory resources, a detail that had been one of the major drawbacks of the third generation of KDE.
Plasma desktop, the first to support widgets
KDE stands out for its Plasma desktop, being the first one designed for Linux that had full support for widgets. Another thing that its users usually like a lot is the use of desktop effects, offering the users a clear interface from which they can select the effects that they want to apply to each action.
So, if you want to have your desktop up to date, and you enjoy using the most elaborate of the Linux desktops, download and install KDE.