And yes, I know what "productive" is in a computing environment and I am most productive with Gnome Shell.
With a single keypress I get a zoom out of everything running on the computer.
With a single keypress I get a terminal to slide down so I can quickly type my commands. Press it again and the terminal slides up.
With a single shortcut I get a search box that lets me directly search in google, wikipedia, youtube, google maps, etc. without having to first open a browser and go to their respective URLs. I can also customize it and add whatever search query I like.
With a single shortcut I can Google Translate any selected text without even opening a browser.
With a single drag I can get the windows I am working with to tile nicely on the screen.
I don't need to manage the virtual desktops because Gnome does that for me, adding and removing desktops as needed.
With a single shortcut I switch between desktops.
With a single keypress I can search through my applications quickly, including the running applications.
I have almost the entire screen available for my applications.
I have skype integrated into the top panel for quick access.
I can disable and enable screen savers with a single click.
I can switch between apps using alt+tab. I can also combine that with the mouse to go directly to what I want instead of continuous alt+tab presses.
I can maximize and unmaximize windows with a single shortcut.
And you can also customize all that with your own code. You also have access to an environment where you can control the DE programmatically.
What else do you need to be productive?