Over the last several months, our Drupal developers have been looking closer at the process of upgrading websites from Drupal 6 to Drupal 7.
In short, it's been reaffirmed that, due to the extremely modular nature of Drupal, an upgrade can be a daunting task. If all the modules for a particular website have good "upgrade paths," (meaning those modules are easily scalable for new updates), the upgrade process could go smoothly.