Returning from the fabled 10.04 LTS, I have tried both 12.04 LTS and Linux Mint 13/16. While the Unity interface has a certain appeal, I found it very unstable and lacking in configuration. The optional Gnome 3 Classic is bugged. It's also a rather weighty distro. In Mint I spent a lot of time plugging holes only to find new ones. I would call this version of 12.04 the "real" LTS, though there's a few rough edges (such as left-over PPAs). The MATE interface doesn't quite live up to the old Gnome 2 yet, but it 'just works'. Hope to see this in 14.04 next year.