We are a web solutions company specialising in FOSS and particularly Drupal and Debian. We build solutions with Drupal, we host them with Debian. We have literally hundreds of servers under our control, all running Debian, we use it for a whole range of purposes - monitoring nodes with Munin and Nagios, web servers running Nginx and PHP-FPM, database servers running Percona and MongoDB, CI with Jenkins, Apache Solr, Ruby products like GitLab for VCS and Redmine for ticketing, some developer workstations, lots of vagrant VMs for development - every single server we run is Debian-backed, whether local development, customer staging or live production.
We chose Debian because we prefer the community, we are more familiar with
its approach to package management and we're very impressed with the speed
of response to incidents like
Heartbleed (the speed of response to
which was a credit to the Debian community).