Version 15.04 is the long-awaited version that comes with some improvement, especially with KDE in Kubuntu.
This improvements can be found in the "VividVervet" release notes. KDE uses now Plasma 5 and KDE Applications 14.12.
LibreOffice 4.4 is included, too.
Did you know KDE has its own messaging service? Perfect for using with KDE Telepathy, which is also integrated.
I already tried the 1.1GB Live-DVD, which can be downloaded directly at Kubuntu.
And again I'm tempted to switch my GNU+Linux distribution.