14 DAY TRIAL // The new KDE Plasma and KDE Frameworks packages are now out of Beta and users can test them in various systems, including Ubuntu. In fact, installing the latest KDE is quite easy now because there is a PPA available.
A lot of users are anxious to use the latest Plasma desktop because it's quite different from the old one. We can call it "the old one" even if the latest branch, 4.14.x, is still maintained until November.
The KDE developers split the project into three major components: Plasma, Frameworks, and Applications. Plasma is actually the desktop and everything that goes with it, Frameworks is made up of all the libraries and other components, and Applications gathers all the regular apps that are usually KDE-specific.
Not everyone will love the new Plasma
Like with all major changes for a desktop environment, the discussion can become pretty heated and there are quite a few users out there (not a majority) who really don't like it. Some of them are even going as far as to say that it somewhat resembles Windows, forgetting that KDE and Windows have shared the same desktop design for a long time.
The truth is that the Plasma desktop has received a much needed facelift. Maybe KDE 4.14.x is one of the best versions released so far and there will be users who will refuse to part with it, even long after it is no longer supported, but the desktop has started to show its age and it no longer fits in with all the other projects.
Even with the PPA now ready and updated with the latest KDE Plasma 5.1.0, which is now stable, users might still encounter some problems. Scarlett Clark, one of the maintainers of this PPA, explains that some NVIDIA issues might be present.
"You absolutely have to have lightdm installed or you will end up without nvidia drivers. Resulting in a black or no screen. Evidently, sddm is not supported yet with nvidia, I filed the bug in hopes this will get resolved. In order to get a functional system I had to chroot into my system from a livecd and reinstall nvidia-331 and allowing it to install alot of unity/gnome stuff (apparently for lightdm?) and it then booted fine," says Scarlett Clark.
Also, keep in mind that just adding the PPA and installing the desktop won't bring all the applications that you're familiar with, like Dolphin for example. You will have to install everything you need manually.
It would be a very good idea to try the new Plasma 5 desktop on a testing machine and not a production one.