Our experience with Content Managements Systems is one of our deepest. Nearly every project we build has at least a light CMS. We often develop custom CMS' for our clients as, we learned long ago that out of the box and brand names are not always better. We find that non-technical editors, business owners, managers, etc. shouldn't have to jump through hoops just to update some site copy. Likewise, not every site or project lends itself well to the standard templating structure of a commercial or open-source CMS platform. These cases as well as many others are better served by a solution custom built to your specifications. "Custom" doesn't always mean more expensive than "customized", as whenever possible we leverage existing frameworks and our own code repository to provide best of breed, field-tested, cost-effective solutions for our clients.
We have also implemented and extended Joomla, Drupal, Mambo, ModX, Expression Engine, Vignette, Sitecore (.NET), and several other open source, commercial, and source-available CMS platforms.