Upgraded to Kubuntu 15.04 Beta1. Plasma 5 looks promising. These are some of the issues found in first look (Mainly UX related, Encountered no crashes/freeze so far). I know that it's "beta" and what exactly that word means :) This is more like my wish-list for the final.

1. Main issues are with Application Launcher, I am unable to change its size. The font size looks real bad and I can't see a place where I can change it. It show a dark square instead of application icons for most of the gnome applications and custom launchers.
2. The "Breeze" UI style is not even for all KDE applications. Some applications renders in old "Oxygen" style eventhough I have selected Breeze in settings. The "KDE Settings" application itself renders in Oxygen style. I have reported it here https://bugs.launchpad.net/ubuntu/+source/kubuntu-meta/+bug/1434516
3. Last but not least, the font settings not working, I have changed changed the fonts in settings but it didn't get effected in the Deskop (Title, taskbar, application launcher etc).

Will try to post some images soon.