I used KDE back in the 2004-2007 time frame then switched to GNOME. Back then, I think GNOME was similar enough to KDE that I hardly noticed much difference. I haven't used KDE since then, but I take it for a spin every 2 years just to see what's going on:

* Ubuntu KDE (Kubuntu 22.04) is one of the few Ubuntu flavors (I think Lubuntu was the other one) that would not automatically scale the font for my 2560x1440 14" screen. So I literally could not read anything in the Installer. I had to peer through a magnifying glass to make it through the installer. Even after logging in, the fonts were so small, I had to keep using the magnifying glass to find the Display (or Monitors?) control panel to set that 175% or 200% option (or was it the 1600x900 screen size option).

* Some (most?) of the various desktop icons seem to be specified in raw pixels. For example, the task bar at the bottom was set to some pixel size which was impossible to read on my laptop screen.

* The KDE UI paradigm seemed familiar, like Windows XP or Windows 7. But the enormous number of configuration options seemed overwhelming for someone who doesn't use KDE all the time.

I normally spend most of my time in the Terminal window and the Firefox browser. I actually don't do a lot of stuff in the graphical desktop. So I want my desktop to be functional but stay mostly out of my way and not require too much configuring and maintenance. KDE always seemed a bit too high maintenance for me.