On my desktop it is Pop!_OS. My laptop is running on Debian MATE, and sometimes I think about switching the desktop to Debian MATE as well. Well, but I'm not that much an OS nerd, I just like to focus on the development hoping to pay minimum attention to the OS running in the background. And most of the time I find MATE easier to use - maybe it is because I learnt the ways of a visual UI in the times of Windows XP =)