I've said this before in other threads, I don't have a problem with KDE being highly configurable (in fact I like that part of it). What i have a problem with is figuring out where the hell controls are located and what they f*cking do.
In my last go around with KDE4, I somehow accidentally changed the background color for the windows that are opened by the widgets on the panel and then wasted an hour of my time trying to figure out how to change it back before I gave up and went back to using Gnome2.
Ironically, KDE4 would be really nice for someone that doesn't want to change anything about it. But if you want to do any customizations, it's like playing Myst, you're reduced to having to randomly click on everything that looks like it might be a control and praying that it won't do something that you can't reverse.
If I could find a good tutorial on KDE4, I might learn to like it. But the only tutorials I've found aren't really very good. If they cover customizing at all, it's only very superficially. They don't cover the obscure stuff that needs it.