Stable/unchanging (zero maintenance for several years, no new bugs appearing out of nowhere), as minimal or bloated as you want it to be (made my own custom live/installer ISO which means I can start fresh with my environment already set up in a matter of minutes), huge number of pre-packaged software, good documentation, identical base distribution across my servers and desktops, mostly sane defaults, community-backed (no or few corporate interests driving the project to shit... look what it did to Ubuntu/CentOS...).

Other Debian-based distributions don't bring anything of value to the table for me, I'd rather use OG Debian.