I used Drupal (6 and 7) in a small bank (80/100 internal users, 500+ financial advisors), building the external public site and also a an internal site used mai

I used Drupal (6 and 7) in a small bank (80/100 internal users, 500+ financial advisors), building the external public site and also a an internal site used mainly to share documents, modules, faq etc.. with the network of advisors. It replaced a commercial solution bringing more clarity (but that was also thanks to stricter rules in place defining types of docs, fields etc..), better graphic appeal (but just because the previous one was really crap) and also great search experience thanks to Apache Solr. As I am a sysadmin, not a developer, I used all built-in modules except one that I modified in order to integrate the authentication with another business system via webservices (only code I developed). As I am also not a graphic, I worked with an external one (that prepared design in PSP so it was a bit a pain to convert it to template) At that time (2009 I think) I reviewed few other options (WP, ezPublish, plone) but I chose Drupal because the authorisation system with roles etc.. was much more powerful than WP one.