mine would be:
pro GNOME
GNOME is way easier to support I guess, as Plasma is huge. GNOME is minimalist, slowly developing and very established.
Also, some unique things especially for interaction with windows:
- best setup dialog
- active directory integration
- online accounts
in general, pro-usability
- calendar, contacts & mail that look well and work well
- simple UI with a tour
- using workspaces really well
Apps
- very modern apps, everthing on flathub and using portals
- software shows flathub app data very well
- epiphany is actually nice and has PWAs
- a ton of GNOME circle apps
contra GNOME
- GNOME breaks Qt apps, even when using Flatpak. On KDE, GTK apps look completely fine.
- app indicators are missing, which are still needed and will probably stay forever
UI
- hitboxes are not at the edges, making no sense
- no maximize button which is strange
- everything is too large and looks like a toy
- without blur my shell, the dark grey looks not good
- the panel at the top makes me look down a bit, which is not good for laptops
- no panel to view my apps by default
general usability
- people need extensions to make it usable, but the API is not stable
- most apps lack features (apart from Inkscape, GIMP and other giants)
- the UI has so little “poweruser” features like desktop entries, deep settings etc., that people need to go straight to the terminal. This is way worse than “having too many settings”.
Apps
- all apps have completely random names, that are not displayed in the GUI and the packages are sometimes called even different from that
- no screenshot utility with editing features
- no image viewer with editing features (Loupe???)
- no kfind
- no batch renaming in files
- no powerful editor
pro KDE
- powerful apps: dolphin, kate, spectacle, okular, systemsettings,
- GNOME apps integrate perfectly, even with dark/light theming support
- traditional layout that doesn’t require using extensions
- a single terminal that is very good ;D
- clipboard menu
contra KDE
- tons of bugs, including memory safety issues
- hard dependency on C++ with apparently less support for Rust bindings, unlike the many already existing Rust+GTK apps
- using Qt which is kinda difficult due to their licensing (reporting backporting fixes)
- no good online account integration, especially for Micro$oft
Apps
- many look old and unpleasant
- no good videoplayer and music player afaik, unlike GNOME circle with Amberol and Celluloid
- the KDE spin overall is bloated with apps (unlike Kinoite, which I would prefer)
- kwallet is very insecure
- kiofuse is probably less well integrated