Er. Don't get me wrong, I like KDE and I like XFCE, but if you're hitting fewer bugs in KDE than XFCE then the least I can say is that your experience is very different from mine. That goes double for resource use, where KDE has made massive improvements but last I looked their file indexer was still a huge resource hog.
I am a big fan of XFCE and I can agree with biggunz. Thunar freaks out randomly. And there were some other issues which I don't remember. Thunar was always the most important one I remember. Talking about the reality shouldn't be the reason for downvotes.
It went on for a few years before it was fixed. In the meantime, I went to i3wm and started using PCManFM. Came back to Thunar after a year or so. But the issue still persisted so went for a while to Nautilus. Only recently was this fixed(I think last year or so?).
KDE is not buggy for most of it's core part and uses less or similar resources wrt XFCE. I use XFCE components cos it's interchangeable and can be used as independent components... Without dragging in a ton of dependencies like in a KDE component.
Am happy as there is a significant improvement in UX with the recent minor/major releases. So am happy and back to using XFCE components.