A current project we're working on at Chocolate Lily involves upgrading a Drupal 6 site to use the Drupal 7 Open Outreach distribution. It's the first time we've used a Drupal distribution for an existing Drupal site instead of a new one.
Change can often be a hard thing for groups—even progressive groups. Getting a staff team to willingly adopt new software or a new website can be challenging. Especially for staff who always feel a shortage of time in getting the important work done.
Any way you do it, upgrading an organizational website to a new major version of Drupal - for example, from Drupal 5 or 6 to Drupal 7 - is a significant task.