I used to run cinnamon for a while when KDE was in the transition process between 4 and 5 (meaning the early 5 versions) and once it stabilised/got all its features back i went back to it, in comparison KDE has a lot more features and stuff in general compared to Cinnamon, of course KDE is a huge community while Cinnamon has mostly been developed by the Linux Mint folks as an alternative to GNOME 3 while still using the shiny new GTK 3 and it might have gotten plenty more features since the last time i tried it.
Either way it fills my soul with joy to see there are fellow penguins in this community .