I've been running Ubuntu and Kubuntu for a few years now, with Ubuntu as my regular PC OS and Kubuntu as an experimental toy more than anything. With the release of Ubuntu 11.04 and the move to Unity I've switched to using Kubuntu as my main PC OS, and Ubuntu is getting wiped off. Unity just slows down the usage of the computer, I was able to switch between and launch tasks far quicker with a task bar and drop-down menus for apps instead of this terribly simplified tablet-style crap. Not to mention they got rid of scrollbars in Gnome so you have to make sure every window is in focus before you can attempt to grab the (non-proportional) scrollbar that appears when you hover over the area long enough for it to pop up near your pointer. I've probably accidently launched LibreOffice about ten times when I only meant to quickly switch to another program with the dock/taskbar (which takes a few seconds to appear and disappear every time you use it).
Ubuntu has become an abomination, but Kubuntu has matured and taken the lead. Although I will always prefer drop-down menus to select my applications rather than a "Start" menu, I still prefer this over the stupid tablet-style interface of Unity, which doesn't even present all available applications and settings anymore, and the only way to find many of them is to click in the Search bar and start searching for it. I could probably write a book on all the things that make Unity and Gnome inefficient and illogical, but the kids won't listen of course. To them if it's new, it must be better than anything that came before it.
Kubuntu is pretty nice looking too, and it seems to be more configurable than the Gnome-based Ubuntu. It reminds me a little of MorphOS.
