Ultimate Edition 2.5 was built off Ultimate Edition 2.4 (Ubuntu 9.10 based), all upgrades pre-installed as of current. It has KDE, Xfce and GNOME, user-selectable at login, three new themes and tons of applications. This release is huge, obviously bigger than Ultimate Edition 2.4. Many tools have been added for new and advanced users. The Ultimate repository also includes the latest updates, as well as software that is not included in the official Ubuntu repositories. More over it is based on Debian.