| Debian has a policy and all packages are made to fit that policy. The policy alows for official packages (apt + dpkg) and local packages (/usr/local/ + stow). The system is designed by many people who each have vested interests in their packages working well. This means that debian packages have sane defaults and often let you change the defaults as it is installed and will tend not to ask the same question again.
Also Debian is a world wide distribution and so is not US-centric which is nice.
Keeping on top of security updates is very quick easy and simple… This must be the selling point to management.
You are not tied to one vendor for support. There are many people and companies who will support Debian.
My humble opinion is that other distribs MAY be easier to set up (they DO have more eye-candy on that we can agree!) but Debian is easier to maintain. Which in the long run is a BIG plus.
Other distribs make it easy for idiots to config a machine… but then you get an idiotic config.
Debian makes it easy for someone who can read, understand and think to configure a machine which results in a well configured and easily maintainable machine. This means that when a new version of debian is released that most of the config is maintained in the upgrade. Once a Debian machine is installed you may _never_ need to boot from floppy again, even when upgrading to a new release! Again Debian proves to be more maintainable than other distribs.