Both default setups of KDE and GNOME are simply legible. Plasma looks like what you’d expect if you’re coming from Windows, with its bottom panel, menu, and task manager, and the defaults are clean and simple, rather welcoming for a new user.
GNOME, on the other hand, is the precise opposite approach: the default metaphor is the opposite of what you’re used to, with no active task management, no desktop icons, no application menu, no dock or taskbar.