I haven't ever really used KDE, and I'm quite sure that it's still not my desktop, but as someone who was aware of the trouble around 4.0, the view I had of the project was that those problems were long gone, and that most people using it today were pretty happy with it.

So I'm not sure whether it's try that that caused a bad reputation that sticks around to this day. (I have other reasons for not preferring it.)