Linux Mint 15 will be named “Olivia” and should be available at the end of May 2013. Olivia is pronounced oh-LIV-ee-ah. It is of Latin origin and the meaning of Olivia is “olive tree”. The olive tree is a symbol of fruitfulness, beauty, and dignity. Linux Mint 15 “Olivia” will feature the following editions: Cinnamon MATE KDE Xfce http://blog.linuxmint.com/?p=2299
Mint has an equivalent called Software Center, though not quite as nice as Ubuntu's. i use Synaptic to install stuff anyway. Ubuntu only seems to offer one desktop/windows manager 'out-of-the-box', unfortunately. unlike Mint who offers more choices.
what i meant is that i don't think Xubuntu and Kubuntu are handled by the Ubuntu team directly. unless i am mistaken, which would not be the first time. i tried Kubuntu a few months back but it was a no-go for me. i'll most likely try both Xubuntu and Kubuntu as well before making a final decision.
Only Ubuntu is officially supported by Canonical. Kubuntu, Xubuntu and Lubuntu are now community-driven distributions.
Regarding Xubuntu, you may be mistaken. Xubuntu - Company / developer: Canonical Ltd. / Ubuntu Foundation Source: http://en.wikipedia.org/wiki/Xubuntu Kubuntu - Company / developer: Blue Systems[1] and community contributors[2] Source: http://en.wikipedia.org/wiki/Kubuntu
Looks like you're right. http://www.ubuntu.com/project/about-ubuntu/derivatives https://wiki.ubuntu.com/DerivativeTeam/Derivatives
They've picked up or are picking up sponsors to continue the project work. Canonical wanted to focus its efforts on Ubuntu. That doesn't mean the other buntus have lost their importance just that their role will be different.
FWIW, Mint is only in the "Known" group ("Known derivatives have not yet chosen to work with the Derivative Team."). ~https://wiki.ubuntu.com/DerivativeTeam/Derivatives