Desktop environments should provide an unobtrusive base for other programs. You should not be fighting with it to get your work done.
I use the Mate desktop environment, which was created to continue the usability, accessibility and customizability features of the Gnome 2 … features that were unceremoniously removed and then presented as the new paradigm of desktop computing by the Gnome 3 project control freaks.
I also do not care for the other overhyped desktop environments, which endlessly and unashamedly imitate the Mac desktop, and project translucent chrome/backgrounds as the more-modern look. Oooh!
I extend my Mate desktop with my own shell scripts and Caja Actions Configurations (custom context-menu extensions).
I do not use the new desktop menu of the Mate desktop. There is an unhealthy competition between all desktop environments to reinvent and redesign the desktop menu. With each new version, you have to learn new ways of doing the old stuff. I do not suffer this madness. I remove the new menu from the desktop and add the Classic Gnome 2 menu in its place. I prefer functionality over flashiness. Microsoft Windows had almost perfected the desktop. Gnome 2 improved it by adding support for multiple workspaces. This made the evolution complete. It needs no further improvement. Desktop environments should just stay out of the way and let us work with more important applications.
KDE
I have known KDE as a solid desktop environment. I have not used it in over a decade. It was quite bloated the last time I used it. (Not slow. Just overdeveloped like a body builder.) Screenshots of the latest versions have not made me want to switch over. If you like KDE, you will do just fine with it. Unlike the condescending Gnome developers, KDE developers do not remove features and call it an improvement.
An update (from February 2024)
Recently, I was forced to use an old laptop. I decided to bring it up-to-date with the latest version of my scripts and utilities. When I wanted to compile FFmpeg from source, I found that the Python3 version was too outdated for compiling some codec libraries required by FFmpeg.
When I compiled Python3 from source and also replaced the old python3, my desktop started behaving like Gnome 3. The title bar of all application windows went missing. All new application windows got stuck to the top-left corner of the screen. I used have a desktop panel aligned to the top edge of the screen. This panel contained the dektop main menu, a subpanel of quick-access launchers (shortcuts) and a subpanel of buttons (taskbar buttons) for all opened windows. As the newly opened windows blocked this panel (and all older windows), the desktop became unusable. I tried to launch the Desktop Settings applet in the Control Center but it would not start. When I ran it from a terminal (as mintdesktop), it threw a python error. I then realized that the old desktop required the old python. When I restored the old python, I was able to open the applet and change the Window Manager from Metacity to Marco. The Mate desktop was unable to run Marco and had switched to Metacity instead.
Apparently, the Mate desktop is able to imitate not just the friendly and usable Gnome 2 style (using the Marco window manager) but also the stupid and useless Gnome 3 style (using the Metacity window manager). I then began to wonder why someone would want to use Gnome 3 window manager when Gnome 2 window manager was available. (That was the whole point of using Mate, was it not?) I could not think of a good reason. Maybe Mac and Mac-style desktop users are suckers for punishment.
One good thing that came out of this horrendous experience is that I was able to compile the latest FFmpeg 7 version, as the latest Git version is newer than the release version. FFmpeg 7 is already due this month.