Tallying my verdicts, I find KDE in first place with 9 points, with five firsts and two seconds. Second is GNOME 2 with 15 points, closely followed by GNOME 3 in third with 16 points. Unity is fourth, with a score of 20.
Of course, this is not the whole story. Memorizing keyboard shortcuts improves the performance of any desktop, but I haven't included them because, in my experience, most people begin working on a desktop with a mouse. Nor have I included extensions that improve the workflow and features of GNOME 3 in particular. My main concern has been how easily users can accomplish common desktop tasks using the default settings
Obviously, personal preferences and priorities affect the scoring. I've never made any secret of my preference -- with some reservations -- for KDE, or my doubts about GNOME 3 and Unity.
Still less did I expect Unity to trail GNOME 3 so much. The explanation, I suspect, is that GNOME 3 is a re-conception of the traditional desktop, while Unity is a simplification aimed at new rather than existing users. But the results do suggest to me that both Unity and GNOME 3 have often over-simplified rather than made simple -- a choice that existing desktop users are unlikely to appreciate.
Possibly, you might disagree with my scoring. However, I've given my reasons for the scoring, so, if you want, you can award points yourself and see what totals you come up with. Like me, you just might come up with some unexpected results.