Started with WordPress but the user roles just failed me ... Couldn't find a solid plugin that filtered content. Drupal provides a much better framework for filtering content based on user roles but...the Views modules make it difficult to create tree hierarchies of your site. http://drupal.org/node/28162 Anyone care to comment?
You can create a hierarchical structure (site architecture wise) using wordpress. Create parent categories and then child categories. However if you meant something else then please elaborate.
Architecture wise, yes. But then when it comes time to displaying your tree (or menu or whatever you call it) WordPress (and Drupal) are very limited in native capabilities. Have you worked with a custom Walker before with the categories? You can extend the Walker class of wp_list_categories. Without doing so, you're simply going to generate a list of either categories or posts of a certain category. There's no hierarchical structure (correct me if I'm wrong).
Yes but for categories only, If you want to actually display the pages related to those categories, a custom walker is needed. So, for example, Category Parent -Category Child -category child page 1 -category child page 2