For several years, I've been saying that KDE is no longer trying to catch up with Windows, but surpassed it several years ago. However, last week a reader challenged me to prove it.
I immediately told him that, if he didn't believe me, he should open KDE and Windows 7 side by side. Even a casual comparison shows that not only does KDE generally have more features than Windows 7, but that, conceptually, KDE has a healthy lead.
While KDE is consistently extending the metaphor of the desktop, Windows 7 is different only in a few minor ways from its first ancestor Windows 95. Moreover, many of these differences are more a matter of fashion, such as displaying icons on the taskbar rather than application names, as they are genuine improvements.
I can say this, despite the fact that Windows 7 comes in several editions, because the differences between these editions is largely in additional applications, not the graphical interface. So far as I can see, the only major exception to this observation is that the Starter edition that ships with notebooks lacks the tools to change the wallpaper or desktop theme.
Otherwise, KDE and Windows 7 invite comparison far more than Windows and GNOME or Unity. Both are oriented towards what might be called a classic desktop, consisting of a panel with a menu, task manager, system tray, clock and calendar, and a workspace for displaying open windows as you work that can be customized with icons and small applications (called "widgets" in KDE, and "gadgets" in Windows 7). These are concepts that are greatly reduced or modified in GNOME and Unity, both of which are deliberate attempts to move away from the classic desktop.
The two may even have some cross-influence, such as a panel of mini-icons for configuring and positioning each widget, and a menu constrained to a window of fixed size.
All the same, whether you are judging by details or conceptually, the pattern is consistent: by any criteria, KDE not only generally equals Windows 7, but offers users more. The comparison is so rarely close that even a pretense of objectivity is soon discarded.
The default contents of panels on classic desktops haven't differed in years. As a result, users moving between KDE and Windows 7 won't find many differences in basic navigation. However, the differences in how features are implemented are obvious as soon as you start configuring.
In both Windows 7 and most implementations of KDE, the panel is placed along the bottom of the screen -- exactly where Windows 95 placed it years ago in an effort not to look too much like Mac OS. In both environments, too, you can lock and auto-hide the panels, reposition them on any side of the screen, add widgets to them as you please, and add extra panels. The most that differs in these basic features is their names.
KDE, though, goes beyond these basics. It allows you to change the width and length of the panel -- to morph it into a dock, in effect, and align it to the left, right, or center of the screen as you please.
Similarly, KDE and Windows 7 have editable menus that display in a fixed window. But Windows 7's gives space mostly to favorites and commonly used applications, leaving only drop-down menus for a list of all programs or shut-down options.
By contrast, KDE's menu offers a series of filtered views, presenting a much less cluttered look without reducing functionality and making the search field more visible. In addition, like earlier versions of Windows, KDE offers a classic menu whose sub-menus open across the desktop, as well as Lancelot, a kind of compromise between the default and the classic menus.
On the other features of the panel, KDE shows the same pattern of matching Window 7's features and adding extras. Because of virtual desktops and Activities (see below), KDE's task bar is potentially more complex than Windows', but you can set what is displayed where exactly as you prefer.