I have a colleague, who's super deep down the Linux rabbit hole and he always ran GNOME. I was never quite sure, if he actually prefers it, or if he just does not care, because he's doing most things in a terminal anyways.

Recently, our IT department made a change, which accidentally switched him over to KDE. He could easily switch back, but he's been checking KDE out instead, and yeah, it's been super interesting.

He definitely has some of that GNOME workflow baked into him. For example, under GNOME you can use Alt + the key above Tab to switch between windows of the same application. In KDE, that shortcut exists, but the default keybinding isn't exactly usable.
Another minor complaint was, for example, that using Meta + arrow-keys doesn't move windows between screens automatically when you press it repeatedly. That's a separate shortcut under KDE, with Meta + Shift + arrow-keys.
EDIT: Apparently, I misunderstood him, his complaint was that Meta + Shift + arrow-keys moves the window between screens in a weird way. It just picks some kind of order for the screens and then goes between them as previous/next, even though you press the left/right arrow keys. There even is the more appropriate shortcut key for left/right, but it's just not the default binding.
Meta + arrow-keys does work for moving windows between screens.

He's aware that he may need to relearn some of his workflow, but yeah, will have to see, if he sticks to it. His emotions are nigh impossible to read, unfortunately. 🙃