I recently switched from Gnome to KDE, after a couple of Gnome quirks proved to be quite irritating. However, KDE became even more bothersome. Specifically the performance was dreadful. This is a new(ish) machine, just a few months old, with a six-core processor, 8 GB of memory, and an SSD, so I expect good if not extraordinary performance. However, under KDE the response within windows was very sluggish, on the order of a second or two to scroll down in applications.
Fonts were also a problem, where the fonts under KDE, for both KDE and Gnome applications, lacking smoothness. Despite much fiddling of font preferences, I could not get them to look as good as they do under Gnome.
Switching back to Gnome hasn’t resolved its irritations, although it’s put them in context. The main problem is that to get the title and task bars working properly (showing the currently focused application) I have to restart the window manager after login, and after launching Gnome Terminal I have to switch in and out of each tab so that the focus of the cursor is correct.