GNOME and KDE is probably the most famous windows manager for GNU/Linux based operating system. This is because major GNU/Linux distro opt to use either one of them as their main Windows Managers.
This move however has divided the users into two major camps, the GNOME and KDE camps. Each Window Manager has its own distinctive style and ways of handling user interaction
I found a nice website that try to compare features available between the two desktop environment (using Ubuntu as a base distro) : KDE and GNOME Environment