 <p>I've worked on a Drupal project with about 1 million nodes. We added transactional support and it wasn't too hard. You'll need to patch the core of course but this shouldn't be a major concern for an enterprise application with good support and documentation. I was working as the observing pair programmer on the transactional support. I think it took us about a day.</p> <p>Edit:</p> <p>I've been working as a Drupal Developer for a few years now. And recently, I have revised my position on Drupal in relation to best practices and enterprise application. </p> <p>I don't think Drupal is particularly suited to the Enterprise space because:</p> <ul> <li>Drupal's testing framework is too cumbersome (a domain specific language would be great)</li> <li>There are too many contributed modules of poor quality </li> <li>Drupal's content model resides partly in code and partly in the database schema </li> <li>Drupal's developer community have become focused on sexy software rather than quality software</li> <li>Drupal doesn't have mature developer tools (drush is changing that) or a development environment built in.</li> <li>Drupal Development is browser and UI centric.</li> <li>The centralized nature of Drupal.org/projects, CVS and Drupal's policy on Contrib Projects inhibits the evolution of individual software projects </li> </ul> <p>Also: The enterprise Drupal Application I was once working on has now been ported into Rails. </p>