I used to prefer Gnome before the KDE 6 update due to the rough edges in KDE. After KDE 6 came out I've tried it again, and it's incredible. The team has spent a lot of time on polish for this major release and it allows KDE's suite of more fully featured applications to shine. GNOME apps like gedit, nautilus, and gnome terminal tend to provide the minimum level of functionality, whereas KDE's applications feel like they're trying to work for power users. Kate goes as far as supporting the LSP for code autocompletion. KDE's desktop is much more customizable as well, so you don't really need extensions to get the functionality you'd be looking for in GNOME, stuff like the application launcher are built in. KDE connect is a really useful application you can install on your phone to get file transfers and notification sharing, among other things, between your phone and computer while connect to the same local network. Performance wise they seem pretty equal, even on older hardware, but KDE might have a bit of an edge in terms of RAM usage, YMMV depending on how you customize the desktop. The one thing I miss about GNOME is their "start menu" experience, I haven't found a way to replicate that in KDE, but I haven't looked very hard either. Overall I wouldn't hesitate recommending KDE, plasma 6 makes me actually feel like the Linux desktop is ready for mainstream.