Max Planck Institute for Informatics, Saarbrücken, Germany
We power our Linux workstations, notebooks and servers with a self-made autoinstallation of Debian. Our "confupdate" package handles the initial installation and hardware detection and configuration as well as upgrades, all non-interactive. Almost all servers (file service, IDM, mail, compute server an SLURM cluster) are also handled this way.
We chose Debian years ago, because we have the full possibility to change everything to our needs and because it is relatively easy to do upgrades (security,...). The well tested state of each release gives us a reassuring stable base to build our additions and upgrades (e.g for new hardware) on.