Directory Wizards Inc, Delaware, USA
Our entire company uses Debian on servers, desktops & Raspberry PI(s), and have been since 2001. It is now used in every aspect of our business and hosts DNS, firewall, VPN, email, web, ftp, SMS gateway, printer servers, backups and more.
Debian was chosen originally for SPARC support but have since migrated to x86_64. It has proven to be one of the most stable platforms we have ever run with almost no downtime.