I've been playing around with both of these lately, tweaking them to look fairly similar.
My setup in both DE's has evolved into what amounts to a classic gnome 2 layout.
And now I've noticed an evolution into a slight preference for XFCE over KDE. And it's not because of performance. My computer has plenty of horsepower, so KDE doesn't slow it down at all. For practical purpose they're about the same speed when handling common tasks.
I admit XFCE's not quite as integrated yet and some of the customizations require a little more work. It's still missing some minor stock features that KDE does have.
Anyone else agree..... or am I just crazy?