Ubuntu MATE 15.04 was released today, this being the first version as an official member of the Ubuntu family. Compared to the previous releases, when the distro was an unofficial flavor, there are numerous changes, including new default applications, a built-in panel layout switcher, new default theme and much more.
For those who are not familiar with MATE, this is a GNOME 2 fork which lets you use the old GNOME 2 desktop interface and applications but it also allows you to use new applications so for instance, you can use Gedit 3 if you want, etc.