All I know about KDE is it has failed for me by being too cluttered with stuff I don't want and not enough stuff I do want. Those pieces that I do want that Gnome doesn't have make me jealous, but I would honestly have to play around with it again to remember what I was I was jealous about because I haven't really needed whatever it was I thought I was missing. I've always managed to find some program to give me what I want.
Of course, once you learn some things that you end up loving you ask yourself, "How could I have ever lived without this?!?!" So I'm either mostly satisfied with Gnome, or I just don't know what I'm missing.
Sometime I'll get around to giving 4.5 a go though to see if anything magical happens to my opinion of the, for me at least, confusing choices they have made for their DE. Like the "lets reduce the size of the desktop where you can put files and folders down to a small window, and make it so you can't put them anywhere else on the desktop" choice for instance. Seriously, what the hell. All you've done is turned it from a big background file manager into a small background file manager. Yay.