Manjaro, because it’s rolling release and it’s built on Arch, only the necessary stuff is installed (including a desktop environment), you can set it up with just a few clicks, and it works out of the box, and even proprietary GPU drivers are easily installable with mhwd. Stable and reliable.
In case anything breaks, there’s quick help on their forum, which (when it happened to me once) outperformed customer support of proprietary software.
It’s been my daily driver for almost 8 years without any major issue.
So in short, robustness, rolling release, simplicity, community.
Edit: I have to add, my use case is for a desktop PC for software design/development + a little gaming.
You mean, MMCCCXIII people.